Kenya's president announced last night that a siege of a Nairobi shopping mall was over, but said that losses from the attack by Islamist gunmen were "immense".
"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 added. He 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.
Video: After final mall siege, Kenya declares national mourning
Somalia's al-Shabab Islamist group said earlier yesterday there were "countless dead bodies" in the shopping mall as security forces searched it for militants, believed to include Americans and a British woman, who seized the building on Saturday.
There was growing speculation the British woman said to have been involved is Samantha Lewthwaite, widow of one of the 2005 London public transport bombers known as "The White Widow".
Kenyan Foreign Minister Amina Mohamed said "two or three Americans" and a British woman were among the militants. She said the Americans were "young men, maybe 18 and 19" years old.
She said they were of Somali or Arab origin and had lived "in Minnesota and one other place".
But Al-Shabab in Somalia rejected suggestions that foreigners were involved.
A burst of gunfire in the early morning broke hours of calm on the fourth day since the militants stormed the Westgate Centre, spraying bullets and lobbing grenades. Helicopters buzzed over the complex, which is popular with foreigners and prosperous Kenyans.
Al-Shabab said it launched the attack in pursuit of demands that Kenya withdraw troops from Somalia.
"There are still gunmen in the building," said an intelligence officer. Asked if there were still hostages, he said: "We are not sure yet."
Al-Shabab said its militants were still holding out and hostages they were holding were still alive.
"There are countless number of dead bodies still scattered inside the mall, and the mujahideen [fighters] are still holding their ground #Westgate," the group said on its Twitter feed.
Al-Shabab, which said it had been in communication with its members in the mall, dismissed the Kenyan minister's comments.
"Those who describe the attackers as Americans and British are people who do not know what is going on in Westgate building," al-Shabab's media office said.
A British security source said it was possible Lewthwaite, the widow of Germaine Lindsay, one of the suicide bombers who killed more than 50 people in London in 2005, was involved in the siege.
Additional reporting by Agence France-Presse