Moscow (Agencies): At least two police officers were killed and about 20 wounded in two successive blasts in Russia's restive North Caucasus region, an official said on Tuesday.

A female suicide bomber blew herself up near a police station in Gubden village of Dagestan on Monday evening, killing one policeman and injuring several others, the official said.

A second blast followed when a car, stopped at Gubden checkpoint for check by security guards while heading toward the scene of the previous blast, exploded killing one policeman and leaving about 17 people injured.

Terrorist attacks on police are common in the troubled North Caucasus republics, especially Dagestan and neighbouring Chechnya and Ingushetia.