MOSCOW, Dec. 4-- At least seven gunmen and ten security officers were killed Thursday in Russia's southwestern Chechen republic, North Caucasus security services said.

"Information available at the moment shows that ten of our officers were killed and up to 20 were injured," the Interfax news agency quoted a source from the security services as saying.

Russian National Anti-terror Committee (NAC) said earlier that seven gunmen were killed in the anti-terrorist operation.

A group of unidentified criminals driving three cars had attacked a road police station and killed three road policemen in Grozny, capital of the republic, at around 1 a.m. local time on Thursday (2200 GMT on Wednesday), NAC said.

Those assailants later broke into a building which was blocked by police, and all the seven gunmen in the building were killed, according to an online announcement released by the NAC.

"Preliminary reports showed that a group of gunmen planned to stage major terrorist attacks in Grozny, but failed thanks to prompt actions taken by law enforcement agencies," head of the republic Ramzan Kadyrov said, who supervised the special operation.

According to the NAC, the operation continues to eliminate another group of gunmen who has entered a secondary school in the city.

Chechnya, one of the republics of Russia's troubled North Caucasus, was hit from time to time by terrorists and Islamic extremists.

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