Hostages held in 'several locations' in Nairobi mall: Kenya govt

An unknown number of hostages are still being held by Islamist gunmen who are locked in a stand-off with security forces inside Nairobi's Westgate shopping mall, the Kenyan government said early Sunday.

"Hostage numbers still unknown, but they are in several locations. No communication as yet. Upper levels (of the mall) have been secured," the government's National Disaster Operation Centre said in a situation update posted on Twitter.

An AFP correspondent at the scene said operations by security forces were continuing, 17 hours after the attack began and as dawn approached in the Kenyan capital.

Somalia's Al Qaeda-linked Shebab rebels have claimed responsibility for the attack, which Kenyan President Uhuru Kenyatta said had left 39 dead and 150 more wounded.

"The work is continuing, but you cannot rush these things," an army officer posted on the perimeter cordon said.

"Our teams are there, we are watching and monitoring, we will finish this as soon as we can."