Three militants who were implicated in twin bombings in the Ingush town of Karabulak on April 5 blew themselves up after being surrounded by police on Friday, Russian investigators said.

A source in the Ingush Interior Ministry said the three militants had been planning a series of new terrorist acts.

One of the dead was Ingush militant leader Akhmed Tsaloev, Ingush President Yunus Bek-Yevkurov told RIA Novosti.

During the police operation in the village of Ekazhevo, a female suicide bomber opened fire at the head of the Nazran police, but hit a district police chief. Nazran is the largest city in Ingushetia. She then blew herself up.

Two police officers were killed and at least 13 people were injured in two explosions in Karabulak in Russia's volatile southern republic of Ingushetia on Monday.

The first blast was carried out by a suicide bomber, who set off an explosive device when he was stopped by security guards at the gates of a police station, killing two police officers and injuring another four.

The second bomb, which was in a car parked opposite the police station in the town, was activated by an unidentified person from a distance. The blast, equivalent to 50 kg of TNT, occurred when an investigative group was inspecting the scene.

MOSCOW, April 9 (RIA Novosti)