Three militants were killed early on Saturday in Russia's North Caucasus republic of Dagestan, a local police official said.

The militants opened fire at police officers when the officers were trying to stop their car for inspection, the official said.

"All three people in the car were killed by retaliatory fire," he said.

Russia has been fighting militants in the North Caucasus for almost two decades, including two brutal wars against separatists in Chechnya.

MAKHACHKALA, May 29 (RIA Novosti)