Two militants, who may be involved in Wednesday's bombing of a hydropower plant in Russia's North Caucasus, were killed in a special operation on Sunday, a local police spokesman said.

A group of at least six gunmen set off five bombs with an estimated total of up to 3 kg of TNT at the Baksan Hydropower Plant in the North Caucasus republic of Kabardino-Balkaria, killing two police officers. The blaze from the blast covered an area of 250 square meters.

"The criminals, who were driving a Volga car, offered armed resistance and were eliminated," the spokesman said.

He added that the militants, Orshokdugov and Seyunov, were on a wanted list. They were, allegedly, involved in a number of grave crimes, including the bombings of the Baksan plant.

He also said that the police seized guns and ammunition from the killed militants.

Russian Interior Minister Rashid Nurgaliyev blamed the attack on lax security arrangements at the plant, saying two of the police officers were asleep at the time of the attack - one in his car and the other in a service room. They were killed instantly in their sleep.

He also said the gunmen had no problem penetrating the plant because it did not have closed circuit television cameras.

Plant head Ali Sattaev said two power units had been damaged as a result of the blasts. However, a RusHydro spokesman said energy supplies to Kabardino-Balkaria would not be affected.

Sechin said earlier on Thursday the reconstruction would cost 1.5 billion rubles ($50 million).

Some experts say the raid on the plant was a "rehearsal" that could be followed by other attacks on infrastructure facilities.

Russian President Dmitry Medvedev warned on Thursday scurity officials and energy company chiefs would be fired if there are more incidents like the bombing of the Baksan hydropower plant.

NALCHIK, July 25 (RIA Novosti)