Communist rebels killed one police officer and then ambushed and shot dead three others on Saturday on the eastern Philippine island of Catanduanes, the local police chief said.
The officers were ambushed after they responded to a report that one of their colleagues had been killed at his home in Pandan town, Inspector Nilo Abines said.
They were attacked by dozens of rebels from the New People's Army (NPA), said Abines. Three officers were killed in the shootout, he said.
The military has dispatched helicopters to the island to help hunt down the rebels.
The NPA is the armed wing of the Communist Party of the Philippines, which has been waging a Maoist rebellion here since 1969 in what has become one of Asia's longest-running communist insurgencies.