Update 5:00 p.m. Kenya's president Uhuru Kenyatta announced his family members are among the now 39 people dead and 150 wounded because of the attack. Kenyatta said security forces were still working to track down the gunmen and secure the mall. "We shall hunt down the perpetrators wherever they run to," he said. "We shall get them. We shall punish them for this heinous crime."

Update 2:54 p.m. The First Lady of Kenya released a statement over Facebook reaching out to her citizens. "I cannot imagine the grief of those who have lost their loved ones and the anxiety of those whose family members are injured or missing," Margaret Kenyatta said. "But with my family, I join all Kenyans in prayer and to offer words of comfort and encouragement."

Update 2:44 p.m. The Associated Press reports al Shabaab are now claiming responsibility for the attack and threatening more actions. The death toll has risen, too: at least 30 people are dead and 60 others are injured because of the attack. Police have sealed off the mall from outsiders while they go from store to store searching for the gunmen. The State Department acknowledged reports that said American citizens were among the wounded but didn't provide further details. "We condemn this senseless act of violence that has resulted in death and injury for many innocent men, women, and children," State Department spokesperson Marie Harf said in a statement

Original Shoppers at an upscale mall in in Nairobi, Kenya were sent scrambling for safety after a pack of gunmen armed with AK-47s and grenades opened fire, killing at least 22 and injuring dozens more, in what police are now calling a terrorist attack. Gen. Abbas Guled, secretary general of the Kenyan Red Cross, told The New York Times over 20 people were killed and 50 wounded following the attack. Those numbers could grow. At first authorities thought the attack was an armed robbery. Now, police are saying it was a terrorist attack. "We are treating this as a terrorist attack," police chief Benson Kibue told reporters, without saying which group was responsible. 

Witnesses described a terrifying scene to the Associated Press: a group of roughly ten gunman, according to police estimates, wearing vests with hand grenades attached and brandishing AK-47s entered Nairobi's Westgate mall around midday Saturday and started shooting into the crowds. "They don't seem like thugs. This is not a robbery incident," one witness told Reuters. "It seems like an attack. The guards who saw them said they were shooting indiscriminately." 

As shoppers scrambled for cover behind anything they could find, the attackers made their targets clear. "The gunmen told Muslims to stand up and leave. They were safe, and non-Muslims would be targeted," Elijah Kamau, who as at the mall during the attack, told the AP. Another witness described watching from another floor as the gunmen allowed certain people in a group to leave the mall safely while firing at those who remained. 

Police showed up half an hour after the attack began. Helicopters circled the mall and urged shoppers to "get out! get out!" as security forces clashed with the armed group inside. With help from the Kenyan military, police entered the mall and started evacuating people shop-by-shop, as sporadic gunfire could be heard from outside the building, in an attempt to flush out the attackers. Some reports say the gunman are still holed up inside the mall, possibly with seven hostages.

It's unclear who is responsible for the attack right now. Most reports are pointing to the Somali militant group al Shabaab, which has carried out similar attacks on Kenyan churches, nightclubs and hotels. Shabaab have threatened to target the Westgate mall, partially because it's popular with wealthy Kenyans and expatriates living in the country. The militant group carries out attacks against countries who have invaded Somalia to combat the group's operation there. Kenya invaded Somalia in 2011.