Updated

Britain on Thursday revised down the number of British people killed in the Nairobi shopping centre attack from six to five, saying one of those previously identified was Kenyan.

"We can now confirm that on present information five British nationals have been killed in the recent terror attacks in Nairobi," a spokesman for the Foreign Office said.

"One individual previously thought to be British is a Kenyan national. Our thoughts are with his family and with the friends and family of all of those who have died during this difficult time."

He said the Foreign Office did not expect to discover any further British fatalities "although we cannot rule out the potential for further British casualties".

"We continue to stay in close contact with the Kenyan authorities as their investigations continue," he said.

British police have sent forensics and counter-terrorism experts to Kenya to help with the investigation into the four-day attack on the Westgate mall, which left at least 67 people dead.

Almost as many are still missing but Kenyan Interior Minister Joseph Ole Lenku said it would take at least a week to fully search the complex, part of which collapsed during the siege.

One of the Britons killed also had an Australian passport.