Rostov-On-Don (Russia): The Russian Interior Ministry on Monday said four of its officers were killed and 16 critically injured during a clash with militants in the mountains of southern Chechnya.

Ministry spokesman Valentin Kalyuzhny said that four militants also were killed and two wounded.

The Interior Ministry said the firefight broke out on Sunday when one of its battalions working with local police came upon a group of about 10 militants, but as darkness fell the surviving militants were able to slip away.

Kalyuzhny said troops resumed their search for the militants on Monday.

Chechnya fought two wars for independence against Moscow in the 1990s but has become relatively quiet in recent years as the insurgency has largely spread to neighboring republics in Russia's Caucasus.