A borderguards headquarters in Russia's North Caucasus republic of Ingushetia has come under fire from grenade launchers, a local police source said.

According to the source, a group of unidentified assailants fired at least two grenades at the borderguards HQ building in the city of Nazran at about 21.45 Moscow time (18.45 GMT) on Wednesday.

No casualties have been reported so far. Police are assessing the structural damage to the bulding and sweeping the area in search for the attackers.

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

Nazran, the largest city in Ingushetia, saw the worst attack in August, when at least 20 officers died in a truck bombing at the police headquarters.

In June, Ingush President Yunus-Bek Yevkurov survived a car bomb attack on his motorcade.

ROSTOV-ON-DON, December 24 (RIA Novosti)