Violence in Libya continued Sunday as rebel forces continued advancing through the city of Tripoli. Most of the city has been captured by the rebels now. They control nearly all of the city. Muammar Qaddafi's sons are in custody with the National Transitional Council, and are likely to be charged by the International Criminal Court. Qaddafi himself is currently missing, with rumors flying that he has either left the city of Tripoli, or the country itself. Rebel fighters and citizens of Tripoli gathered in Green Square to celebrate the apparent fall of Muammar Qaddafi, and took the time to rename it Martyr Square, as it was before Qaddafi came to power. President Obama weighed in Sunday evening, saying, "the momentum against the Qadhafi regime has reached a tipping point." Our live blog of the events from Sunday can be read below. 

Original post: It's down to "zero hour" in Libya, according to the Libyan Rebel Council, as rebel forces approach Qaddafi in Tripoli. Yesterday there were rumors that Qaddafi had already fled the city with his two sons, and the White House itself indicated today that Qaddafi's "days are numbered." Nonetheless, Qaddafi has maintained that his forces would defend the city with "their last drop of blood." We will update with developments from Tripoli as they come in.

12:20 a.m.: We are signing off. Come back tomorrow morning for more coverage. 

11:47 p.m.: Outlook in Tripoli is beginning to get better

BBC News' Matthew Price reports from the Rixos Hotel in Tripoli, where most foreign journalists are staying during the conflict: 

"The overall picture in Tripoli is patchy. There are certainly large areas, where the opposition is in control. But some areas are still under government control. However, one of the most vivid signs of the collapse of the Gaddafi regime is that government employees have been slowly leaving our hotel - the place from where Libya's state TV has been broadcasting."

He also filed a story for BBC News describing his experiences in the hotel with other journalists and government officials since the fighting began: 

We gathered - the international media together - to work out what we might do. Body armour on, escape routes chosen. No route to the port, no boats there to take us out anyway.

Then the hotel chef came up and asked us if we would like dinner.

We dined in flak jackets - helmets by our side. And as the Iftar meal, the breaking of the fast ended, so too did the relative silence.

Heavy weapons opened up again, explosions outside the hotel.

11:04 p.m.: More gunfire in Green Square

CNN's Sara Sidner has told Wolf Blitzer there's been more gunfire in Green Square. She said it seemed like it was coming from snipers on nearby roofs, but it was unclear. [Clarification: The footage that aired was from an earlier time in the evening. Sidner went into the square with rebels when a sniper fired from a nearby rooftop. The CNN crew was forced behind the pillars in the square. She was unharmed. Sidner did tweet this shortly after 11p.m.: "Green square nearly empty. We were warned to get out. Rebels say Gadhafi troops advancing toward square."]

10:52 p.m.: Head of National Transitional Council says Mohammed Qaddafi has not been hurt

As a follow up, Al Jazeera spoke to the NTC, who said Qaddafi's sons are now in custody, and Mohammed Qaddafi is fine. Al Jazeera Arabic was interviewing him earlier Sunday when the interview was cut short after gunshots were heard on the other end of the phone line before the line went dead. The head of the NTC told Al-Jazeera he was not hurt. Video of the interview can be seen here:

Rebels told Al-Jazeera they had control of the whole city now, except for Qaddafi's Bab Al-Azizyah stronghold. 

10:38 p.m.: Obama says the conflict against Qaddafi's has come to "a tipping point"

Via The Weekly Standard, President Obama issued a statement Sunday evening on the situation in Libya: 

Tonight, the momentum against the Qadhafi regime has reached a tipping point. Tripoli is slipping from the grasp of a tyrant. The Qadhafi regime is showing signs of collapsing. The people of Libya are showing that the universal pursuit of dignity and freedom is far stronger than the iron fist of a dictator.

The surest way for the bloodshed to end is simple: Moammar Qadhafi and his regime need to recognize that their rule has come to an end. Qadhafi needs to acknowledge the reality that he no longer controls Libya. He needs to relinquish power once and for all. Meanwhile, the United States has recognized the Transitional National Council as the legitimate governing authority in Libya. At this pivotal and historic time, the TNC  should continue to demonstrate the leadership that is necessary to steer the country through a transition by respecting the rights of the people of Libya, avoiding civilian casualties, protecting the institutions of the Libyan state, and pursuing a transition to democracy that is just and inclusive for all of the people of Libya. A season of conflict must lead to one of peace.

The future of Libya is now in the hands of the Libyan people. Going forward, the United States will continue to stay in close coordination with the TNC. We will continue to insist that the basic rights of the Libyan people are respected. And we will continue to work with our allies and partners in the international community to protect the people of Libya, and to support a peaceful transition to democracy.

10:28 p.m.: Rumors of another clash; South African ambassador speaks; NATO involvement increased

CNN's Sara Sidner tells Wolf Blitzer that rebels in Tripoli are on the move and getting prepared for a battle in the city. She was in Green Square but crowds have been cleared out in preparation. She said the feeling has become slightly more tense, and there are rumors that Qaddafi forces are "on the way." 

South Africa's ambassador to Libya, Mohammed Dangor, told Al-Jazeera he had no knowledge of any South African planes in Libya. He said he already left Libya on Saturday with most of the other South African representatives in the country. Some remain behind for now, though. 

"I have no knowledge of any South African planes in Tripoli ... but Nato should know, since they control the airport and no plane can land without their permission," he said.

The New York Times is reporting NATO and the United States played a larger role in preparing the rebels to invade Tripoli over the last few weeks: 

The officials also said that coordination between NATO and the rebels, and among the loosely organized rebel groups themselves, had become more sophisticated and lethal in recent weeks, even though NATO’s mandate has been merely to protect civilians, not to take sides in the conflict.

NATO’s targeting grew increasingly precise, one senior NATO diplomat said, as the United States established around-the-clock surveillance over the dwindling areas that Libyan military forces still controlled, using armed Predator drones to detect, track and occasionally fire at those forces.

9:24 p.m.: Chavez speaks out; Mohammmed under house arrest, interviewed, and shot at

Venezuelan president Hugo Chavez has spoken out against NATO's involvement in the conflict in Libya. Appearing on state television in Venezuela, he criticized the United States and European countries for "destroying Tripoli with their bombs." 

"Today we are seeing images of the democratic governments of Europe, along with the supposedly democratic government of the United States destroying Tripoli with their bombs," Chavez said. "Today they dropped I don't know how many bombs."

He asked Velezuelans to, "Pray to God for the Libyan people." Per the Associated Press, Chavez said the attacks were oil-motivated and caused damage to schools and hospitals.
 
Al-Jazeera Arabic spoke with Mohammed Qaddaffi on air, who is now under house arrest in Libya. Mohammed, "took a very apologetic tone and said it was a lack of wisdom that caused the revolution and crisis in Libya." The interview was interrupted by sounds of gunfire and explosions, and eventually cut short with no indication of his safety.
 
Al-Jazeera English's Zeina Khodr is in the former Green Square and reported this video of the celebrations there: 
 
 

8:10 p.m.: Libyans celebrate in a renamed Green Square

Ujala has been relieved, and Connor will take over this live blog. First, a quick rundown of things that have happened since our last update:

Libyans have gathered in Tripoli's Green Square to celebrate the fall of Tripoli to Libyan rebels, CNN reports. On television, CNN is reporting that the celebrating Tripoli citizens have renamed it "Martyr's Square," the original name of that part of the town. Qaddafi had changed the name to Green Square. This image, from Getty, shows the size of the crowd there:

Additionally, Qaddafi's sons will be sought by the International Criminal Court for war crimes: 

International Criminal Court chief prosecutor Luis Moreno-Ocampo also said Saif Gadhafi had been arrested and would be sought by court "for his participation in crimes against humanity (affecting) the Libyan people."

The court, based in The Hague, earlier this summer issued an arrest warrant for Saif Gadhafi as well as his father and uncle Abdullah al-Sanussi. Moreno-Ocampo said the court plans Monday to contact authorities associated with those holding Saif al-Islam to try to arrange for his transfer to the Netherlands for an eventual trial.

Reuters reports President Obama isn't making a statement until he has full confirmation on what's happening. He's currently on vacation in Martha's Vineyard. 

6:30 p.m.: Tripoli Surrenders

Libyan military forces in Tripoli have now officially surrendered to the rebel forces, according to Al-Jazeera TV.

6:15 p.m.: Qaddafi Speaks Again, Unlikely from Libya

This is very dangerous...Why would you allow this to happen? How can you let Tripoli, which was beautiful and safe, how can you allow this? This must not happen... Otherwise you will remain servants of the imperialists... and the British imperialism will return once again... All the men and women must come out, in order to prevent the traitors and agents from Tripoli... Now all of the tribes are marching... from the western mountains, because they have heeded the call... there is no place for the agents of imperialism... not in front of these huge masses which are marching to Tripoli right now... Those who understand Islam, they must take all the women -- the women we trained to use weapons -- they must also march...

The full speech was longer and more rambling. According to Al-Jazeera, no one knows where Qaddafi is, though some have suggested he has been granted political asylum in Algeria by its President Abdelaziz Bouteflika and is there now. But Al-Jazeera TV says it can confirm that he is "definitely, definitely not in Tripoli," he left "maybe even weeks ago."

Meanwhile: CNN confirms another Qaddafi son has been captured: Saadi Ghaddafi.

6:05 p.m.: NATO Secretary's General has issued a statement:

NATO is ready to work with the Libyan people and with the Transitional National Council, which holds a great responsibility. They must make sure that the transition is smooth and inclusive, that the country stays united, and that the future is founded on  reconciliation and respect for human rights.

5:45: Qaddafi Speaks: Vows to Stay Until the End

From an audio recording, Qaddafi spoke: he gave a rallying call to the tribes to come into Tripoli.

"The West will not protect you. How can you allow for Tripoli to be burned? ...Beautiful Tripoli they will turn it tomorrow into a destroyed city... you must lead now and march... Those who understand Islam properly must go out and lead the people, go out, take your weapons, there should be no fear. Those who work for the imperialists there are but a few."

Additionally, another report on his sons: from Al Arabiya: Mohammed, the eldest son of Muammar Gaddafi gave himself up & Saif Al Islam was captured." And Al-Jazeera TV reports that people are celebrating in Tripoli, though there is still resilience in some areas from Qaddafi forces. From their video feed, there are scenes of people stamping on rugs with Qaddafi's image.

5:15 p.m.: Moussa Ibrahim speaks, saying that in 11 hours 1,300 people killed, 5,000 people injured. He blames NATO, asking for negotiations.

"These armed gangs would not be able to move...you cannot condition peace, you need to sit down and talk...Why has the right to say you cannot discuss this?.. All NATO cares about is how to destroy this political system so that it can fulfill its deires, not the desires of the Libyan people, but the desires of NATO... We are very resilient, and still very strong... the death toll will increase and increase, each side is terrified of the other side, so let's stop... We need our leader Qaddafi, without him both sides would collapse and make it easy prey for the other side."

He also said reinforcements were coming, and "people would not give up... Qaddafi should lead us for our peace, democracy, and negotiations."

5:00 p.m.: Qaddafi's sons reportedly captured.

France 24 is reporting that Gomaa Al Komati of the Libyan NTC said: I confirm that Saif Al Islam has been captured. We believe Qaddafi is now in Algeria. Al-Jazeera English confirmed that Saif Al-Islam had been captured, and confirmed that the presidential guard had surrendered.

Both sons are captured, according to other reports -- from Al Jazeera: sources confirm arrest of Qaddafi's two sons: Saif Gadafi and Sady in Tripoli Libya.

CNN is confirming there's currently a fierce gun battle outside the Rixos hotel in Tripoli, and Al Arabiya reports Gaddafi presidential guard surrenders to rebels, citing rebel national transitional council." Sky News describes the scene in Tripoli: "These scenes are amazing - there are hundreds of people who have come out onto the streets to greet this convoy of rebel soldiers. You can hear them singing and dancing, it is an amazing scene."

4:30 p.m.: Security brigade surrenders, and UNCONFIRMED reports that Qaddafi may even be dead.

Al-Jazeera says brigade in charge of Gadhafi's security surrenders and lays down arms, according to Reuters. Reports are that there is singing and dancing -- with even women and children out in the streets: "Scenes in Tripoli are 'absolutely amazing' with many hundreds of people on the streets celebrating."

Malik Al-Abdeh, Chief Editor of the Syrian pro-democracy satellite channel Barada TV, tweeted: "CONFIRMED: Mu'amar , leader of for 42 years, has been shot DEAD in vicinity of Rixos Hotel in ."

4:00 p.m.: Libyan rebels marched into parts of Tripoli on Sunday evening, pushing past the city’s outer defense lines and setting off celebrations in some western neighborhoods of the capital, the New York Times reports. Al-Jazeera reports that Libya rebels arrived in the Green Square in Tripoli Center. 

3:00 p.m.: Al-Jazeera reports that Libya's defected ex-prime minister Abdes Salam Jalloud said Sunday he believed it was too late for his former ally Muammar Gaddafi to strike a deal to leave power and he would likely be killed. In an interview with Italian media he said: 

I believe the regime has a week left, 10 days at most. And maybe even less. He has no way of leaving Tripoli. All the roads are blocked. He can only leave with an international agreement and I think that door is closed.

I think it would be difficult for Gaddafi to give himself up. And he is not like Hitler who had the courage to kill himself... I don't think the evolution of the situation in Tripoli will allow him to survive.

2:30 p.m.: Libyan rebel forces reportedly in outskirts of Tripoli, taking over military base. Fox News reports:

Euphoric Libyan rebels have pushed to the western outskirts of Tripoli without meeting any resistance after they overran a major military base that defends the capital... giving them access to large stores of weapons...

Hours earlier, the same rebel force of hundreds drove out elite forces led by Muammar al-Qaddafi's son in a brief gunbattle. The fighters hauled off truckloads of weapons and advanced full speed toward the capital...

NATO has reportedly been bombing Qaddafi's Tripoli compound continuously, though no casualties have been reported yet.

2 p.m.: Germany and France have acknowledged Qaddafi's losing battle and asked him to step down, the AP reports. French President Nicolas Sarkozy urged Gadhafi to "spare his people further useless suffering" by stepping down immediately. He also said that the outcome of the 6-month-long conflict "is no longer in doubt."

1 p.m.: Qaddafi will stay until the end, and Libyan government denies loss of control to rebels. Qaddafi issued a new audio message played over state television on Sunday saying he will stay in Tripoli "until the end" and calling on his supporters to help liberate the capital from a rebel offensive, according to the New York Times. He said he was "afraid that Tripoli will burn." Rebel troops claimed to have broken Qaddafi’s “ring of steel” defense and advanced upon the city. Nonetheless, government spokesman Moussa Ibrahim maintained on state TV said that city remained well-defended by “thousands of professional and volunteer soldiers” loyal to the government and that “the situation is under control.”

12:30 pm: Libyan rebels may hope to avoid a battle in Tripoli. "Libyan rebel forces ill-equipped to fight their way into a city the size of Tripoli may look to locally brokered deals or a burgeoning popular uprising to break the will of Muammar Gaddafi's forces," Reuters reports.

Gauging the loyalty of Tripoli's population is far from easy. Gaddafi loyalists have put on many marches and demonstrations of loyalty in recent months, but hundreds if not thousands of his opponents also took to the streets in the early stages of the uprising before they were cowed. The rebels will hope security forces will melt away...

"I think they'll wait on the outskirts and hope for either an uprising or that Gaddafi decided to call it a day and leaves," said David Hartwell, Middle East analyst for IHS Jane's

Reuters adds that "Some say Gaddafi himself might already have fled, perhaps to his hometown of Sirte or a desert base further south. The long speeches at boisterous public meetings have given way to broadcast addresses delivered on scratchy telephone lines."

12 p.m.: The White House has predicted that Muammar Gaddafi's days as leader of Libya are numbered, from Al-Jazeera:
"The United States continues to communicate closely with our allies, partners, and the (rebels' Transitional National Council)... We believe that Gaddafi's days are numbered, and that the Libyan people deserve a just, democratic and peaceful future," said White House spokesman Josh Earnest.