A suicide bomber killed at least two policemen in Russia's Ingushetia region, the latest in a spate of attacks.

More than 50 people have been killed and 100 injured by suicide bombers over the past week in the Moscow metro and the mainly Muslim regions of Dagestan and Ingushetia in Russia's North Caucasus.

Today's bombing in Ingushetia came exactly a week after twin suicide attacks in the Moscow metro raised concerns of a new wave of strikes by militants from the North Caucasus against major Russian cities.

In the latest attack, a male suicide bomber tried to enter police headquarters in the town of Karabulak, about 20km from the Ingush regional capital of Magas.

‘A suicide bomber tried to get into the police headquarters during roll call, but after being stopped the bomber detonated the explosives,’ Oleg Yelnikov, a spokesman for Russia's Interior Ministry in Moscow, said by telephone.

Two police were killed immediately and a third was injured.

Less than an hour after the suicide attack, a second bomb in a car opposite the police station was detonated.