A bomb exploded late Saturday at Defense Department headquarters, raising fears of continued unrest after a seccessionist revolt ended on the Philippines' second-largest island.

The explosion was at the same military camp where authorities held the leader of the Mindanao island rebellion, Col. Alexander Noble, who surrendered earlier Saturday.One bystander was injured and two jeeps were destroyed by the bomb. Officials said it was made of the same materials used by right-wing military rebels in a series of bombings in Manila since mid-August.

Guards immediately closed the gates at the sprawling Camp Aguinaldo and barred anyone from entering or leaving. The camp has been on alert since the revolt erupted Thursday on Mindanao island.

It was the 36th explosion in the Manila area since Aug. 13 in what the military believes is a terror campaign by rightist rebels.