KENYA'S president announced overnight that a siege of a Nairobi shopping mall was over, but said losses from the attack by Islamist gunmen were "immense'' and 67 people had died.

"We have ashamed and defeated our attackers, that part of our task is completed,'' President Uhuru Kenyatta said in a televised address to the nation.

"Our losses are immense,'' he said. "We have been badly hurt, but we have been brave, united and strong. Kenya has stared down evil and triumphed. We have defeated our enemies and showed the whole world what we can accomplish.''

Mr Kenyatta said 61 civilians and six members of the security forces died in the siege. He said five attackers had been killed and that there were 11 suspects in custody. The president also called three days of national mourning.

A group of attackers marched into the four-storey Westgate Mall at midday local time Saturday, spraying shoppers with automatic weapons fire and tossing grenades.

Somalia's al-Qaida-linked al-Shebab rebels said it carried out the attack in retaliation for Kenya's military intervention in Somalia.

The president said "three floors of the mall collapsed, trapping several bodies within the rubble including those of terrorists.'' Police said the current death toll was provisional, with the Kenyan Red Cross saying 63 people were still listed as missing.

In one of the worst attacks in the country's history, a group of attackers marched into the four-storey, part Israeli-owned Westgate Mall at midday Saturday local time, spraying shoppers with automatic weapons fire and tossing grenades.

Mr Kenyatta said that "forensic investigations are underway to establish the nationalities of all those involved'' amid reports Americans and a British woman were among the insurgents.

There has been growing media speculation at the possible role of wanted British extremist, known as "The White widow", Samantha Lewthwaite, daughter of a British soldier and widow of suicide bomber Germaine Lindsay, who blew himself up on a London Underground train on July 7, 2005, killing 26 people. Lewthwaite is wanted in Kenya, and is accused of links to the Shebab.

The president said intelligence reports had suggested that a British woman and two or three American citizens "may have been involved in the attack'', but said could not yet be confirmed.

Kenyan army chief Julius Karangi has said the attackers were from "different countries''. Many foreign fighters, including Somalis with dual nationalities, are members of the Shebab force.

Close to 200 were wounded in the four-day long carnage, which saw running battles between militants and security forces in the complex, popular with wealthy Kenyans, diplomats, UN workers and other expatriates. The siege developed into a hostage drama with Shebab claiming hostages were being held, and Kenyan special forces - who were backed by Israeli, US and British agents - describing the stand-off as delicate.

Police said earlier overnight that explosive devices set up by the militants were defused in the mall, with part of the roof collapsing after a fierce fire the day before.

Boy, 4, faces off with gunmen

Earlier, it emerged that a four-year-old boy trapped in the Kenya shopping mall massacre confronted a gunman who later gave the boy a Mars bar. Elliot Prior, from Windsor, Berkshire, told one of the terrorists that he was a ''very bad man'' as he protected his mother, Amber, who had been shot in the leg, and six-year-old sister Amelie, the Daily Mail UK reports.

The gunman then handed the boy and his sister Mars bars before telling them: ''Please forgive me, we are not monsters''.

The amazing story emerged as Kenyan troops tightened their grip on Islamists making their final stand in the deadly shopping mall siege, on the fourth day of the attack.

Sporadic shooting at the upmarket Westgate mall broke out again at dawn, hours after officials had claimed Kenyan troops were in "control" of the sprawling complex.

As the interior ministry said early Tuesday that all hostages trapped by the militants are believed to have been freed, Kenyan Foreign Minister Amina Mohamed said that several American nationals and a British woman were among the fighters.

The latest developments come after an off-duty member of Britain's special forces reportedly helped save a hundred lives as terrorists launched their attack.

The Daily Mail reports sources as crediting the soldier as a hero of the Nairobi siege after intervening with a handgun as his only weapon.

The soldier was reportedly having coffee at the Westgate mall when it was attacked by a group of 10 to 15 terrorists.

His story emerged after he was photographed - gun tucked into his pants - helping to guide two women away from the carnage. He is said to have then returned to the building which was ringing with intense gunfire.

A friend in Nairobi said: "What he did was so heroic," a source said to be a friend of the soldier told the MailOnline. " He was having coffee with friends when it happened. He went back in 12 times and saved 100 people. Imagine going back in when you knew what was going on inside."

British special operations troops regularly train in Kenya to gain experience in a jungle environment.

Although Kenyan security forces have previously said they have taken control of the shopping mall, they now say they are still fighting "one or two" terrorists and an explosion and gunfire have been heard around dawn in Nairobi, or mid-afternoon in Australia.

'White Widow' among the dead?

Earlier this morning, the body of a white woman was reported to have been found among terrorists killed when Kenyan troops stormed the besieged shopping mall.

Reuters reports three separate sources as stating the woman's body was found with those of terrorists killed in the assault, fuelling speculation she is the "white widow" Samantha Lewthwaite - the widow of Britain's 7/7 bomber Jermaine Lindsay.

Police, however, have told reporters that they are still investigating the possibility the woman may have been a hostage dressed in one of the terrorists' clothes as a "decoy" during the attack which saw Kenyan authorities regain control of most of the four-storey shopping mall.

Kenyan Foreign Minister Amina Mohamed has confirmed that "two or three Americans'' and "one Brit'' were among those who attacked the mall. She said in an interview with the PBS NewsHour program 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 attacker from Britain was a woman who has "done this many times before,'' Mr Mohamed said. Lewthwaite, known as the "White Widow" to Britain's tabloid media, is a 29-year-old mother of four, from the Home Counties. She is believed to be a leading figure in Somali terror organisation al-Shabab.

She is also wanted for questioning in relation to a series of coordinated suicide attacks in central London on July 7, 2005, in which her husband blew himself up. A double-decker bus and several underground trains were attacked, killing the four suicide bombers and 52 civilians.

However, an al-Shabab military commander this morning told the BBC that no British or American nationals had been involved in the attack. Abu Omar said the reports were "baseless", as were claims women had been among the terrorists who had stormed the shopping centre.

MORE: 'White Widow' linked to Kenyan terror attack

Kenya's interior ministry confirmed the deaths of three of the estimated 10 to 15 al-Shabab militants as it declared victory in regaining control of the shopping mall.

It has since backed down on the claim, saying instead that it now believed all hostages had been released and that police and special forces were still "sanitising" the complex.

The ministry said authorities had detained and were questioning 10 people in relation to the attack.

Sheikh Ali Mohamud Rage, an al-Shabab leader, told a radio station in Somalia that the remaining attackers will fight to the death, calling the massacre part of a global jihad.

"This is a holy war between believers and non-believers,'' he said, calling for more attacks.

Loud explosions and sustained gunfire were heard several times in the past 12 hours in the upmarket Westgate shopping centre, and black smoke continued to billow in the evening from a blaze that authorities said was started by the attackers.

Slow but steady assault

Kenya's interior ministry early this morning Australian time claimed its troops are now "in control" of the shopping centre.

"We're in control of Westgate,'' the ministry said in a post on Twitter, some 60 hours after Islamist gunmen stormed the complex and massacred at least 62 people.

"Our forces are combing the mall floor by floor looking for anyone left behind. We believe all hostages have been released" cc @MEsipisu — InteriorCNG Ministry (@InteriorKE) September 23, 2013

"Our forces are combing the mall floor by floor looking for anyone left behind. We believe all hostages have been released.''

Officials shortly after attempted to hose-down the "victory" claim.

"Our special forces are inside the building checking the rooms. Obviously it's a very, very big building," said government spokesman Manoah Esipisu.

"We think that everyone, the hostages, have been evacuated, but we don't want to take any chances," he said.

"The special forces are doing their job and yes, I think we are near the end."

"The special forces call this sanitising. It's a very complex and very delicate operation," he said, but said no resistance was being encountered.

"At the moment they have not met any resistance, but of course we are not ruling out the possibility that there are a couple of them hiding in a remote room or corner," he said.

KDF contInue to secure the Westgate mall Building. Official statement on status of the operation to be issued later. — InteriorCNG Ministry (@InteriorKE) September 23, 2013

The announcement came almost two days after the up-scale mall was seized by members of a Somali terrorist group who invaded with guns blazing.

Kenyan President Mr Kenyatta, whose nephew was killed along with his fiancee, called the attack "despicable and beastly''.

The al-Shabab rebels said the carnage was in retaliation for Kenya's military intervention in Somalia where they are battling the Islamists.

Shebab spokesman Ali Mohamud Rage has said the brazen assault was in retaliation for Nairobi's two-year battle against the extremists' bases in southern Somalia.

On Tuesday, he threatened further ``black days'' if Kenya did not bring troops home, warning the siege was just ``a taste of what we will do''.\

For his part, Kenyatta vowed ``full accountability for the mindless destruction, deaths, pain, loss and suffering we have all undergone.''

"These cowards will meet justice, as will their accomplices and patrons, wherever they are.''

Shocked witnesses said the attackers weeded out non-Muslims for execution by demanding they recite the Shahada, the Muslim profession of faith. Children were also executed.

As well as scores of Kenyans -- from ordinary workers to the president's nephew -- many of the dead include foreigners, including six Britons, as well as two Canadians, a Chinese woman, a Dutch woman, two French women, two Indians, a South African and a South Korean.

``The people who did this, they are vigilantes, they are animals,'' British businessman Louis Bawa, whose eight-year-old daughter and wife were killed, told the Daily Telegraph.

Away from Westgate, Nairobi on Tuesday appeared to have returned to largely business as usual, but the attacks have shocked Kenyans deeply.

Blood donor appeals ended after banks filled with donations from hundreds, while over $650,000 (490,000 euros) has been raised to support the families affected.

Israeli interests in Kenya have come under attack before, and the Westgate mall -- frequented by well-to-do Kenyans, diplomats, UN workers and other expatriates - has long been seen as a potential target.

The siege, which has revived memories of the 2008 Mumbai attacks, is the worst attack in Nairobi since an al-Qaida bombing at the US embassy killed more than 200 people in 1998.

US President Barack Obama, whose father was Kenyan, has called Kenyatta offering "whatever law enforcement support that is necessary''.

Intelligence sources from two foreign countries who could not be named said there had been no leaks or ``chatter'' ahead of the attack, despite close monitoring of the Shebab's operations, suggesting the insurgents may have come from a different cell.

Shocked witnesses said the gunmen tried to weed out non-Muslims for execution by interrogating people on their religion or asking them to recite the Shahada, the Muslim profession of faith.

The dead include six Britons including a British-Australian, two French women, two Canadians including a diplomat, a Chinese woman, two Indians, a South Korean, a South African and a Dutch woman, according to their governments.

Also killed was Ghanaian poet and former UN envoy Kofi Awoonor, 78, while his son was injured.

RELATED: Mother describes 'immeasurable' loss of son Ross Langdon

Former President mourns Yavuz "loss'

Stmt from my father @billclinton, my mother @hillaryclinton and me on the tragic death of one of our staff in Kenya: http://t.co/4OFBlDp6NA — Chelsea Clinton (@ChelseaClinton) September 24, 2013

Former US president Bill Clinton has paid tribute to the wife of the Australian architect killed in Kenya.

Tasmanian-born Ross Langdon and his doctor wife Elif Yavuz were expecting their first child in just two weeks when they were gunned down by Islamist attackers at Nairobi's shopping centre at the weekend.

The Harvard-educated Dr Yavuz worked with the Clinton Foundation during her doctoral studies and recently rejoined the institution as a senior vaccines researcher based in Tanzania.

Mr Clinton, former US secretary of state Hillary Clinton and their daughter Chelsea say they were "shocked and terribly saddened" to learn of Dr Yavuz's death.

"Elif was brilliant, dedicated, and deeply admired by her colleagues, who will miss her terribly," they said in a statement.

"Elif devoted her life to helping others, particularly people in developing countries suffering from malaria and HIV/AIDS.

"On behalf of the entire Clinton Foundation, we send our heartfelt condolences and prayers to Elif's family and her many friends throughout the world."

US President Barack Obama addresses Kenyan attack

Mr Obama says the US stands with Kenya against the "terrible outrage" of a shopping mall terrorist attack.

Mr Obama says the US is providing law enforcement assistance and all the help it can to deal with the tragedy.

Mr Obama was making his first public remarks on the attack while meeting with Nigeria's president on the sidelines of the United Nations Monday. Mr Obama had called Kenya's president over the weekend to offer condolences and support.

Mr Obama said the attack shows the international community must stand against the "senseless violence" he said groups like al-Shabab represent.

Kenya's foreign minister has said "two or three" American citizens were among the gunmen. He described them as "young men, between maybe 18 and 19, and of Somali or Arab origin.

Hostages detailed

Yesterday, Kenyan officials announced that "most" hostages had been rescued. But no numbers were given. Kenyan officials have never said how many hostages they thought the attackers had, but have said preserving the hostages' lives is a top priority.

Kenyans and foreigners were among those confirmed dead, including British, French, Canadians, Indians, a Ghanaian, a South African and a Chinese woman. The UK Foreign Office said Monday it has confirmed the deaths of four British nationals.

From neighbouring Somalia, spokesman Sheik Ali Mohamud Rage for al-Shabab - the militant group that claimed responsibility for the attack - said in an audio file posted on a website that the hostage takers had been ordered to "take punitive action against the hostages" if force was used to try to rescue them.

At the Oshwal Centre next to the mall, the Red Cross was using a squat concrete structure that houses a Hindu temple as a triage centre. Medical workers attended to at least two wounded Kenyan soldiers there on Monday.

Terrorists tweet

Al-Shebab said on a Twitter feed, an account that appears to be genuine, that the attackers had lots of ammunition. The feed said that Kenya's government would be responsible for any loss of hostages' lives.

As the crisis surpassed the 48-hour mark, video taken by someone inside the mall's main department store when the assault began emerged. The video showed frightened and unsure shoppers crouching as long and loud volleys of gunfire could be heard.

The Shebab extremists stormed the mall on Saturday from two sides, throwing grenades and firing on civilians.

Shebab is an extremist Islamic terrorist force that grew out of the anarchy that crippled Somalia after warlords ousted a longtime dictator in 1991. Its name means "The Youth" in Arabic, and it was a splinter youth wing of a weak Islamic Courts Union government created in 2006 to establish a fundamentalist Islamic state in the East African nation.

Shebab is estimated to have several thousand fighters, including a few hundred foreign fighters. Some of the insurgents' foreign fighters are 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.

International Criminal Court

International Criminal Court chief prosecutor Fatou Bensouda offered Tuesday to help prosecute those behind the deadly attack on Nairobi's Westgate shopping mall, a statement said.



Ms Bensouda expressed "her deep sympathy to the victims of the appalling attack", which "may constitute a crime" under the ICC's founding Rome Statute, to which Kenya is a party.



"With full respect for the primacy of jurisdiction of the Republic of Kenya, the prosecutor stands ready to work with the international community and the government of Kenya to ensure that those responsible for these crimes are brought to justice," Ms Bensouda said.

In an unprecedented decision, judges at the International Criminal Court have excused Kenya's vice president from his crimes against humanity trial for a week so he could return home to help deal with the Nairobi mall hostage crisis.

At a hastily arranged hearing, Presiding Judge Chile Eboe-Osuji said William Ruto could leave on a morning flight to Kenya.

The hearing was quickly halted and Mr Ruto was rushed to the airport.

Mr Ruto is the first such high-ranking politician to go on trial at the court while still in office.

Even before his trial started this month, his defence lawyers had asked judges if he could stay in Kenya for much of the trial to attend to his duties as deputy head of state. Trial judges allowed the move, but prosecutors appealed the decision, saying Ruto should be present.

Prosecutors did not object to his returning home on Monday.