Kenyan police on Monday said they had arrested more than 10 suspects for questioning over an ongoing attack on a Nairobi shopping mall where more than 60 people were massacred.
"We've arrested more than 10 individuals for questioning in relation to the Westgate attack," police said in a message on their Twitter account.
Kenyan security forces remained locked in a fierce battle with Somali Islamist gunmen inside the upmarket mall on Monday, where thick black smoke billowed out following huge explosions.
Kenya's defence ministry said that "three terrorists have been killed so far", while "a few others have suffered injuries."
Operations continued but troops had "sealed all possible escape routes", the ministry said in a statement, adding that the chances of any terrorists escaping were "very slim."
A Kenyan security source and a Western intelligence official said Israeli forces were also involved in the operation, along with British and US agents.
Somalia's Al Qaeda-linked Shebab insurgents have claimed the attack, which began midday on Saturday, when the gunmen marched into the complex, firing grenades and automatic weapons and sending panicked shoppers fleeing.
Meanwhile the interior ministry has said the fire in the mall has been contained, although plumes of smoke continued to dominate Nairobi's skyline as night fell.