Police has grabbed hold of a video footage showing a notorious gang leader in Russia's North Caucasus known as Alexander Tikhomirov or Said Buryatsky just minutes before he was killed in a FSB sweep, a law enforcement source said on Saturday.

The video was shot on a mobile phone which belonged to one of the killed militants. It shows Tikhomirov saying his last prayers and bidding farewell to his comrades in a house in the village of Ekazhevo.

"In the video, one can clearly see and hear the militants saying good-by to one another, after they have realized that they can't break out of the police surrounding," the source said, adding the phone was found in the house.

At least six militants were killed and 15 others detained during a special operation on Tuesday in the southern Russian republic of Ingushetia. Police found scores of illegal weapons and bomb-making materials at the site.

Further investigation revealed that Tikhomirov and the other militants were preparing a terrorist attack in the North Caucasus region involving suicide bombers.

"Said Buryatsky himself was responsible for training suicide bombers. The received operational data have helped prevent a large terrorist act," the source said.

Fierce fighting had erupted earlier on Tuesday near the region's largest city, Nazran, when a group of heavily armed militants were holed up in several houses and refused to surrender.

According to police, the militants had been involved in recent attacks on law enforcement officials, and planted bombs near police headquarters in Ingushetia.

Russia's mainly Muslim North Caucasus republics, especially Chechnya, Dagestan and Ingushetia, have seen an upsurge of militant violence lately, with frequent attacks on police and officials.

The Kremlin has pledged to wage "a ruthless fight" against militant groups but also acknowledged a need to tackle unemployment, organized crime, clan rivalry and corruption as causes of the ongoing violence in the region.

Moscow announced an end to its decade-long antiterrorism campaign against separatists in Chechnya in April 2009, but has since had to step up the fight against militants as skirmishes and attacks on police and other officials have continued.

MOSCOW, March 6 (RIA Novosti)