A police officer has died of his injuries after an explosion at a nursery in Russia's North Caucasus republic of Ingushetia, police said Monday.

The officer had been called to the scene after a booby-trapped grenade launcher was discovered. The grenade launcher subsequently exploded, but no one was injured. However, the dead officer was among three police and three civilians who were caught in a blast when a second device detonated.

"Doctors did all they could, but failed to save police officer Khamkhoyev," a police spokesman said.

The power of each explosion was equivalent to 800 grams of TNT.

Russian President Dmitry Medvedev recently ordered the Federal Security Service to tighten security in the North Caucasus following a suicide bomb attack in nearby Dagestan that killed five people and wounded up to 19 on January 6.

ROSTOV-ON-DON, February 1 (RIA Novosti)