Nairobi attack: Kenya's President Kenyatta says siege over Published duration 24 September 2013

media caption President Uhuru Kenyatta: "We have shamed and defeated our attackers"

Kenya's President Uhuru Kenyatta has declared the end of a bloody four-day siege by Islamist militants at Nairobi's Westgate shopping centre.

Five attackers were shot dead by troops and 11 suspects were in custody, he said in a TV address to the nation.

Kenya has "shamed and defeated our attackers" but the "losses are immense", he said, confirming that 61 civilians and six soldiers had died.

Three days of national mourning have been declared, starting on Wednesday.

As the clearing of the mall continues, Kenya is braced for the death toll to rise further.

Several bodies - including those of "terrorists" - are thought to be trapped under rubble after three floors of the building collapsed following a blaze on Monday, officials said.

Some 175 people were injured in the attack; 62 people remain in hospital and many others are being treated for shock and are undergoing counselling.

"I promise that we shall have a full accountability for the mindless destruction, deaths, pain, loss and suffering we have all undergone as a national family," the president said.

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

At least 18 foreigners are among the dead, including six Britons, as well as citizens from France, Canada, the Netherlands, Australia, Peru, India, Ghana, South Africa and China.

Continued threat

The militants stormed the Westgate centre on Saturday, throwing grenades and firing indiscriminately on shoppers and staff.

Somali Islamist group al-Shabab said it had carried out the attack in retaliation for Kenyan army operations in Somalia.

The president said he could not confirm reports that a British national and two or three US citizens were involved in the attacks, but he said forensic experts were carrying out tests to ascertain their nationalities.

In an interview with the US TV programme PBS Newshour, Kenya's Foreign Minister Amina Mohamed said the Americans were 18 or 19 years old, of Somali or Arab origin.

Her remarks have fuelled media speculation about the possible involvement of Samantha Lewthwaite , the widow of one of the men who carried out attacks on London's transport system on 7 July 2005.

But a Twitter post from al-Shabab on Tuesday evening dismissed claims that women were involved in the attack. The group said it "categorically" denied involvement of any woman".

The group said: "We have an adequate number of young men who are fully committed and we do not employ our sisters in such military operations."

President Barack Obama called the events in Nairobi a "terrible outrage" and said the US was providing all the co-operation it could to Kenya.

Somali Prime Minister Abdi Farah Shirdon said those behind the attacks "must be held accountable."

Al-Shabab, which is linked to al-Qaeda, has repeatedly threatened attacks on Kenyan soil if Nairobi did not pull its troops out of Somalia.

There are about 4,000 Kenyan troops in the south of Somalia as part of an African Union force supporting Somali government forces.

Al-Shabab is fighting to create an Islamic state in Somalia.

Despite being pushed out of key cities in the past two years, it remains in control of smaller towns and large swathes of the countryside.