MOSCOW: Russian security forces Saturday killed four militants in a special operation in Russia's troubled southern region of Dagestan, officials said.

"Four militants who showed armed resistance were liquidated" in the clash in the Khasavurtovsky region of Dagestan, an official with the local branch of the Federal Security Service (FSB) told the Interfax news agency.

The official said that three of the dead had already been identified as known members of a local militant group planning attacks.

The militants had been surrounded in a private house and opened fire when they were asked to surrender, the reports said.

In a related incident one policeman was killed and another wounded in Moscow Saturday when they came under fire from attackers suspected to be natives of Dagestan, officials said.

The police were responding to a report of a family brawl in Moscow's western region of Kuntsevo in the early morning when they stopped a suspicious car. But then came under fire from the vehicle while checking the driver's papers.

The district's police chief Ivan Krasnykh told Russian news agencies that according to preliminary information the occupants of the car were three men from Dagestan.

"While the documents were being checked, they suddenly opened fire on the policemen," he was quoted as saying by the Interfax news agency. The police then returned the fire.

Junior lieutenant Denis Kleimovich was killed on the spot while sergeant Konstantin Bykov was seriously wounded in the shoulder and stomach and is now in intensive care, he said.

The assailants fled and police have mounted a major hunt for them. "For us it is a matter of honour to find and arrest these bandits," said Krasnykh.

Moscow's police chief Vladimir Kolokoltsev rushed to the scene overnight, Interfax said.

Dagestan and other regions of the Russian northern Caucasus have been the scene of regular deadly clashes in recent months between Islamist militants and security forces amid an escalating insurgency.

But deadly attacks on the security forces in the Russian capital are extremely rare.