HYDERABAD (AFP) -- Three policemen were shot dead and another critically injured when Maoist rebels attacked a police station in southern India, police said Saturday.

About 10 rebels dragged the four officials out of the police station in southern Andhra Pradesh state and shot them at point-blank range after tying them to trees, a police spokesman who did not wish to be named said.

The guerillas then bombed the police station in Nalgonda district, which borders the state capital Hyderabad.

The incident occurred nearly four weeks after police killed eight suspected rebels in the state.

The rebels shouted slogans saying the killings were a retaliation against last month's police operation and then fled.

Left-wing rebels are active in 15 of India's 29 states, including Andhra Pradesh.

The Maoist guerrillas claim to be fighting for the rights of neglected tribes and landless farmers.