India ? Security forces searched the heavily forested mountain areas of northeastern India’s troubled Manipur state Sunday, a day after 16 policemen were killed in a rebel ambush, an official said.

Army, police and paramilitary soldiers are searching the area where the attack took place and have recovered a cache of weapons, the state’s police chief A.K. Parashar said. He did not give details about the kind of weapons found.

The attack involved 40 to 50 heavily armed rebels, Parashar added.