Much of the violence in the Caucasus region so far has been confined to Chechnya, Dagestan and Ingushetia [AFP]

At least 12 deaths have been reported in the Caucasus region of southern Russia amid fighting between suspected separatists and security forces.

A group of seven armed men - and three police officers - were killed in a raid on Tuesday at an abandoned farm on the border between Karachayeva-Cherkessia and Stavropol provinces in the western part of the region, Sergei Kulik, a police spokesman, revealed.

The suspects were believed to be behind an attack on a police car earlier this month, in which three officers were killed.

Violence in the province is less frequent than in neighbouring Dagestan, Ingushetia and Chechnya, where deadly attacks take place almost daily.

Separately, two suspected suicide bombers were reportedly killed on Tuesday in Chechnya's capital, Grozny, after police, acting on a tip-off, confronted the pair.

There were conflicting reports emerging whether they were shot by police, or detonated explosive belts.

No police officers were injured there, Ramzan Kadyrov, the Chechen leader, said.

Ethnic strife

The gun battle on the Karachayeva-Stavropol border has stirred fears that violence continues to spread across the ethnically divided Caucasus.

The epicentre of attacks continues to be in Dagestan, where two suicide bombers killed four and injured 27 on Monday night.

One of the bombers behind the attack in the Dagestan mountain village of Gubden has been identified as Marina Khorosheva, a young Russian woman linked to a failed suicide attack in Moscow's Red Square on December 31.

She and her husband, Vitaly Razdobudko, had aroused media interest as Orthodox Christians who converted to Islam - leading press to dub them "the Russian Wahhabi".

Samples of the second bomber's body has been sent for DNA analysis, said police, who said they could not confirm it had been Razdobudko behind the attack.

"For now, this is nothing more than speculation, because the suicide bomber's body was blown to bits," a police spokesman said.