In the largest terrorist attack in Kenya since the 1998 bombings of two American embassies, masked gunmen associated with the Somali militant group al-Shabab stormed an upscale mall, killing at least 59 people and taking an unknown amount hostage.

After a tense standoff overnight, with armed forces surrounding the mall, any attempt to engage the terrorists has been placed on hold while authorities try to determine where and how many hostages they have. In a Twitter post, al-Shabab has said there will be no negotiations with the Kenyan government, the New York Times reports.

At noon Saturday, around 10-15 gunmen burst into the Westgate mall, a popular destination for wealthy Kenyans and foreign visitors. After reportedly instructing all Muslims to leave, the gunmen began firing on civilians, leaving a horrifying scene with shoppers taking cover and wheeling out the wounded in shopping carts. By Saturday night, bodies littered the steps of the monument to Kenya's relative prosperity. French, Chinese, British, Ghanaian and Canadian citizens have been reported as among the dead.

As the attack reached its 24th hour, Kenyan interior minister Joe Lenku stressed that any further operations would have to be "very, very delicate." Kenyan forces will soon attempt to free the hostages being held by the Muslim fighters, who have vowed to fight to the death. Al-Shabab claims that there are 36 hostages in the mall.

Civilians are still escaping from the mall more than a day after the initial attack. Cecile Ndwiga tells the BBC that she had spent the day hidden under a car in the parking garage, because "the shootout was all over - left, right."

Al-Shabab has claimed that the attack was in retaliation for Kenya's military presence in Somalia. Kenyan armed forces have repeatedly attacked al-Shabab forces close to the Kenyan border, where 4,000 Kenyan troops are stationed in southern Somalia.

In a speech on Saturday night, Kenyan president told citizens that Kenya would remain “as brave and invincible as the lions on our coat of arms.” He then admitted that he had lost close family members in the attack.

Using methods similar to the 2008 hotel attack in Mumbai, the gunmen quizzed victims on their Muslim beliefs, making them pray and answer questions about the religion. If they failed to answer correctly, they were killed.

[Associated Press]