Manila: Police in the Philippines say communist rebels have exploded a land mine and opened fire on a patrol vehicle east of the capital, killing four and wounding five officers.

Police commander Leocadio Santiago says government troops have joined a manhunt for the New People's Army rebels in Rizal province following Tuesday's ambush, one of the latest flare-ups in the decades-old insurgency.

He said about 20 rebels hiding in the bush along the road in the remote township of Baras outnumbered police when they opened fire then detonated a mine under the vehicle. The rebels fled after taking away at least nine M16 rifles.

The rebels have dismissed as propaganda the military's vow to crush them by the time President Gloria Macapagal Arroyo ends her term in June.