Kenya’s president announced Tuesday that a siege of a Nairobi shopping mall was over, but said losses from the attack by gunmen were "immense" and at least 67 people had died.

Kenya's president announced Tuesday that a siege of a Nairobi shopping mall was over, but said losses from the attack by gunmen were "immense" and at least 67 people had died.

"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," President Uhuru Kenyatta said in a televised address to the nation.

Kenyatta noted that 61 civilians and six members of the security forces died in the incident, where five attackers had been killed and that there were 11 suspects in custody.

The toll was provisional, he indicated, saying "three floors of the mall collapsed, trapping several bodies within the rubble including those of terrorists," calling three days of national mourning.

A group of attackers marched into the four-storey Westgate Mall at midday Saturday, spraying shoppers with automatic weapons fire and tossing grenades. Somalia's Shebab movement claimed the responsibility over the attack.

Kenyatta said "intelligence reports had suggested that a British woman and two or three American citizens may have been also involved in the attack."

"We cannot confirm the details at present but forensic experts are working to ascertain the nationalities of the terrorists," the Kenyan President added, promising to punish all those responsible.