On Tuesday evening in Kiev, police moved in on an anti-government protest camp in the center of the city. The police forces, some armed with water canons and stun grenades, issued an ominous warning for women and children to leave, the AFP reported. As the police moved in on the protesters, their camp was "engulfed in flames," according to the AP. According to the latest count by the AP, at least 18 people have died in the clashes: seven police officers and 11 protesters. 

We've embedded a livestream below of the scene, and will provide more updates here as they're available. 

The latest confrontation came at the end of a deadly day of protests in the country. At least nine people, including at least two police officers (although some later reports say four), have reportedly died in a new round of clashes between Ukrainian protesters and police in the city of Kiev, though there are varying reports on the death toll from today's violence. And it looks possible that the number will rise. (Update, 10:40 p.m.: It has. CNN has "at least" 21 dead.)

Opposition medics told the AFP on early Tuesday that at least as 150 people were injured, dozens of them seriously, in the clashes. 

The U.S. State Department issued an emergency warning to American travelers in the country due to the escalating confrontations between police and protesters: 

The Ukrainian Security Services have announced that following today’s violence they may take extraordinary measures beginning this evening (February 18). The Embassy advises all Citizens to maintain a low profile and to remain indoors tonight. The Kyiv Metro (subway) has been shut down and access into Kyiv by road has, according to credible reports, been restricted.

The thousands of government protesters who turned up in Kiev on Tuesday are frustrated with the country's Parliament, prompting the new round of demonstrations this week. Essentially, the governing body of the country has delayed action on a measure that would limit the president's powers, part of a compromise deal to end months-long opposition protests there. That presidential limitation is a key demand of the protesters, the AP explains, and many are worried that it won't happen quickly enough — or at all.

Here's how they describe the scene earlier on Tuesday: 

As parliament delayed the session to take up the issue, thousands marched toward the parliament building to put pressure on lawmakers. Shouting "shame!" the demonstrators hurled stones at police and set trucks blocking their way on fire. Law enforcers retaliated with stun grenades and fired what appeared to be small metal balls, as smoke from burning tires and vehicles billowed over central Kiev. Dozens of protesters and police were injured, as well as journalists working for The Associated Press and the Reuters news agency.

Ukrainian president Viktor Yanukovych first angered opposition groups in November, when he took a loan from Russia instead of moving forward with an agreement with the EU. A compromise deal was supposed to resolve some of those tensions this week — until Russia offered to give the Ukraine another needed cash loan, just as Yanukovych's government reopened talks with Western European leaders. Protesters are worried that the president will deepen the Ukraine's connection to Russia, at the expense of its relations with the EU. That question is a huge one in the country, with deep cultural, historical, and political tensions at play. 

If the Parliament does pass the measure limiting Yanukovych's power, the Parliament, and not the President, will get to pick the next Prime Minister of the country. Ukraine's previous Prime Minister Mykola Azarov resigned along with his government in late January after sustained protests in the country. If Yanukovych gets to pick Azarov's replacement, however, opposition leaders are worried that he'll simply pick a Russian loyalist and keep strengthening ties to Moscow. 

Meanwhile, it appears that Yanukovych isn't taking calls from many Western officials: 

 Although Vice President Joe Biden did (at least eventually) get through. Here's the readout of their call: 

Vice President Biden called Ukrainian President Viktor Yanukovych today to express grave concern regarding the crisis on the streets of Kyiv.  He called on President Yanukovych to pull back government forces and to exercise maximum restraint. The Vice President made clear that the United States condemns violence by any side, but that the government bears special responsibility to de-escalate the situation. The Vice President further underscored the urgency of immediate dialogue with opposition leaders to address protesters’ legitimate grievances and to put forward serious proposals for political reform.  The United States is committed to supporting efforts to promote a peaceful resolution to the crisis that reflects the will and aspirations of the Ukrainian people. 

Senator John McCain, on the other hand, called on Obama to take action and propose sanctions against the Ukraine if Yanukovych stays in power.

"We have to side with the protesters and the power has to be dispersed from the hands of Yanukovych, who changed the constitution and put virtually all power in the hands of the President," he told CNN's Jake Tapper

McCain also warned against Russia's interference in Ukraine's affairs, though that doesn't appear to be an issue at the moment. According to Hvylya, Putin isn't taking Yanukovych's calls. 

Opposition leader Vitali Klitschko met with Yanukovych overnight, but told reporters that talks went nowhere.

"Yanukovych said that there is only one option," Klitschko said. "To clear Maidan and that everyone has to go home."

Yanukovych issued a statement (in Ukrainian) early Wednesday morning. According to the BBC, he blamed opposition leaders for the outbreak of violence.

Update, 2:47 a.m.: Here's part of Yanukovych's statement blaming protesters for the violence:

I again call on the leaders of the opposition ... to draw a boundary between themselves and radical forces which are provoking bloodshed and clashes with the security services ... If they don't want to leave (the square) — they should acknowledge that they are supporting radicals. Then the conversation with them will already be of a different kind.

The Ukrainian Health Ministry has raised the death toll to 25, and more 240 others have been injured. According to CNN, violence has also spread to western Ukraine, where protesters have apparently been attacking police and local government officials.

Among the casualties is one Ukrainian journalist, Vyacheslav Veremiy.

This post on a developing story has been updated with new information