Associated Press journalists at the Westgate mall said the explosion on Sunday afternoon was by far the largest in the 30-hour siege. There was silence after the big blast.
An estimated 10 to 15 militant attackers are in the shopping mall holding an unknown number of captives. The Kenyan military has gone into the four-story mall and there have been sporadic gun battles. Some Kenyan military were seen carrying in at least two rocket propelled grenades. Earlier military helicopters hovered over the mall.