The operation took place in Russia's volatile North Caucasus region, RIA Novosti says, citing the Federal Security Service on Sunday.

The security operation was conducted from December 23 to December 25 near the village of Verkhny Alkun in the Sunzha District of Ingushetia which borders troubled Chechnya, the Federal Security Service said.

During the operation that lasted more than 15 hours, all the militants were killed despite their fierce armed resistance. The militant group of the so-called Ingush sector of the southwestern front included 12 gunmen led by warlord Vakhi Dzhenaraliyev who had been on the federal wanted list for attacks on police and federal troops, the Federal Security Service said.

The security forces, which suffered no casualties during the security operation, also seized a large arsenal of arms and ammunition, the Federal Security Service said.

Ingushetia, which borders Chechnya, has seen a marked increase in fighting between militants and federal troops this year.