Speculation is growing that terrorism suspect Samantha Lewthwaite from Northern Ireland, dubbed the White Widow, had been killed as Kenyan military forces attempted to end the three-day siege at a Nairobi shopping mall.
Americans and a British woman were among the terrorists who attacked the mall, killing more than 60 people, Kenya's foreign minister said today.
Amina Mohamed said the attackers included "two or three Americans" and "one Brit". She told the PBS NewsHour programme that the Americans were 18 to 19 years old, of Somali or Arab origin and lived "in Minnesota and one other place" in the US.
The woman is believed to be Lewthwaite, from Banbridge, who is already wanted in Kenya on terror charges.
A Muslim convert, she had been dubbed the "white widow" because of her marriage to Jermaine Lindsay, who blew up an underground train at King's Cross in London in 2005, killing 26 people.
She has been on the run in east Africa for two years after allegedly plotting to attack Western targets in Kenya.
Her father was a British soldier posted in Northern Ireland during the Troubles, who married a local woman.
Lewthwaite converted to Islam in her teenage years and later married Lindsay, one of the 7/7 London bombers.
She then married another jihadist while on the run in Africa where she became a leader of the al-Shabaab terror grouping.
Lewthwaite later arranged the assassination of a terror rival in an attack that also claimed the life of her second husband, Habib Ghani. She did not even acknowledge the fact he had been murdered.
Family friends in Banbridge yesterday said the publicity surrounding Lewthwaite in recent years had deeply affected her grandmother who lives near the town centre.
Elizabeth Allen is said to be devastated by the revelations regarding her grand-daughter.
It is understood the stress on Ms Allen, who is in her late 80s, is such she was hospitalised recently.
The frail pensioner previously told how she was issued with a panic alarm with which she was to contact police if Lewthwaite ever made contact with her.
Kenyan security forces battled al Qaida-linked terrorists in the upmarket mall for a third day in what they said was a final push to rescue the last few hostages in a siege that has left at least 62 people dead.
While the government announced that "most" hostages had been released, a security expert with contacts inside the mall said at least 10 were still being held by a band of attackers described as "a multinational collection from all over the world".
US officials said they were looking into whether any Americans were involved. State Department spokeswoman Jen Psaki said the department had "no definitive evidence of the nationalities or the identities" of the attackers.
The security expert, who insisted on anonymity to talk freely about the situation, said many hostages had been freed or escaped in the previous 24-36 hours, including some who were in hiding.
But there were at least 30 hostages when the assault by al-Shabab militants began on Saturday, he said, and "it's clear" that Kenyan security officials "haven't cleared the building fully".
Flames and dark plumes of smoke rose above the Westgate shopping complex for more than an hour yesterday after four large explosions rocked the surrounding neighbourhood. The smoke was pouring through a large skylight inside the mall's main department and grocery store, where mattresses and other flammable goods appeared to have been set on fire, a person with knowledge of the rescue operation said.
The explosions were followed by volleys of gunfire as police helicopters and a military jet circled overhead, giving the neighbourhood the feel of a war zone.
By evening, Kenyan security officials claimed the upper hand.
"Taken control of all the floors. We're not here to feed the attackers with pastries but to finish and punish them," police inspector General David Kimaiyo said on Twitter.
Kenya's interior minister Joseph Ole Lenku said the evacuation of hostages had gone "very, very well" and that Kenyan officials were "very certain" that few if any hostages were left in the building.
But with the mall cordoned off and under heavy security it was not possible to independently verify the assertions. Similar claims of a quick resolution were made by Kenyan officials on Sunday and the siege continued. Authorities have also not provided any details on how many hostages were freed or how many still remain captive.
Three attackers were killed in the fighting yesterday, authorities said, and more than 10 suspects arrested. Eleven Kenyan soldiers were wounded in the running gun battles.
Somalia's al Qaida-linked rebel group, al-Shabab, which said it carried out the attack, said the hostage-takers were well-armed and ready to take on the Kenyan forces.
An al-Shabab spokesman, Sheik Ali Mohamud Rage, said in an audio file posted on a militant website that the attackers had been ordered to "take punitive action against the hostages" if force was used to try to rescue them.
The attackers have lots of ammunition, the militant group said in a Twitter feed, adding that Kenya's government would be responsible for any loss of hostages' lives.
A Western security official in Nairobi said the only reason the siege had not yet ended would be because hostages were still inside.
Westgate mall, a vast complex with multiple banks that have secure vaults and bulletproof glass partitions, as well as a casino, was difficult to take, the official said. "They are not made for storming," he said of the labyrinth of shops, restaurants and offices. "They're made to be unstormable."
At least 62 people were killed in the assault on Saturday by 12 to 15 al-Shabab militants wielding grenades and firing on civilians inside the mall, which includes shops for such retail giants as Nike, Adidas and Bose and is popular with foreigners and wealthy Kenyans.
The militants specifically targeted non-Muslims, and at least 18 foreigners were among the dead, including six Britons, as well as citizens from France, Canada, the Netherlands, Australia, Peru, India, Ghana, South Africa and China. Nearly 200 people were wounded, including five Americans.
Fighters from an array of nations participated in the assault, according to Kenya's chief of defence forces General Julius Karangi. "We have an idea who these people are and they are clearly a multinational collection from all over the world," he said.
Al-Shabab, whose name means "The Youth" in Arabic, said the mall attack was in retribution for Kenyan forces' 2011 push into neighbouring Somalia. It was the deadliest terrorist attack in Kenya since the 1998 al Qaida truck bombing of the US embassy in Nairobi, which killed more than 200 people.
An extremist Islamic terrorist force that grew out of the anarchy that crippled Somalia after warlords ousted a long-time dictator in 1991, al-Shabab is estimated to have several thousand fighters, including a few hundred foreigners, among them militants from the Middle East with experience in the Iraq and Afghanistan conflicts. Others are young, raw recruits from Somali communities in the United States and Europe.
For years Minnesota has been the centre of a government investigation into the recruiting of fighters for al-Shabab. Authorities say about two dozen young men have left Minnesota since 2007 to join the group. Minnesota's Somali community is the largest in the US.
Somali president Hassan Sheikh Mohamud said the attack showed that al-Shabab was a threat not just to Somalia but to the international community.
Reports that some of the attackers may have been Somalis who lived in the United States illustrate the global nature of the militant group, the Somali leader said in a speech at Ohio State University.
"Today, there are clear evidences that Shabab is not a threat to Somalia and Somali people only," he said. "They are a threat to the continent of Africa, and the world at large."
As the crisis passed the 48-hour mark, a video emerged that was taken by someone inside the mall's main department store when the assault began. It video showed frightened and unsure shoppers crouching as long, loud volleys of gunfire could be heard.
Kenyans in many parts of the country stood in long lines yesterday to donate blood to aid the nearly 200 people injured in the attack. Fund raisers collected hundreds of thousands of dollars, though government officials warned of scam artists taking advantage of the tragedy.
Ms Mohamed said Kenya needed to work with other governments to fight the increasing terrorist threat and "much more with the US and the UK, because both the victims and the perpetrators came from Kenya, the United Kingdom and the United States. From the information we have, two or three Americans and so far I've heard of one Brit".
She added: "That just goes to underline the global nature of this war that we are fighting."