London -

British Prime Minister David Cameron was cutting short his stay with Queen Elizabeth II on Monday to return to London to hold an emergency meeting on the Nairobi shopping mall siege.

Cameron has been staying with the monarch at her private Balmoral estate in Scotland - an invitation traditionally offered to the prime minister's family in September.

The British government's emergency response committee COBRA met for a second time on Sunday over the attack at a Nairobi shopping mall.

Three British nationals have been confirmed among the 68 killed, with the Foreign Office saying that one of the three was a British-Australian national.

“I'm cutting short a visit to Balmoral to return to Downing Street to chair COBRA late this afternoon, dealing with the Kenya terror attacks,” Cameron said on his Twitter account.

Kenyan troops were still fighting Islamist militants at Nairobi's Westgate shopping mall on Monday, almost 48 hours after the attack began. - Sapa-AFP