At least 13 people were injured in a series of two explosions in Russia's volatile southern province of Ingushetia, a local investigative committee spokesman said.
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 VAZ 2112 car stolen in the Ukrainian region of Donetsk and parked opposite the police station in Karabulak, was activated by an unidentified person from a distance. The blast, equivalent to 50 kg TNT, occurred when an investigative group was inspecting the scene.
"As a result of a first explosion two police trainees were killed and another four injured," the spokesman said. "After the car explosion nine people were injured - seven police officers, the deputy prosecutor of the Karabulak police and one civilian."
On March 29, two deadly blasts occurred in two Moscow subway stations claiming some 40 lives and injuring dozens more. The attackers struck the Lubyanka and Park Kultury stations during the morning rush hour.
Chechen militant leader Doku Umarov claimed responsibility for the metro attacks, saying in a video message they were revenge for a special operation carried out by federal security forces on February 11, 2010, when 18 militants and four civilians were killed in Ingushetia. He threatened further attacks.
The Russian counter-terrorism committee said the organizers of the recent terrorist attacks in Moscow and Kizlyar and some of the suicide bombers have been identified.
President Dmitry Medvedev said the bombings were all links in the same chain, while Prime Minister Vladimir Putin said a single terrorist group carried out the attacks.
Russia has been fighting militants in the North Caucasus for almost two decades, including two brutal wars against separatists in Chechnya.
MOSCOW, April 5 (RIA Novosti)