MAKHACHKALA, September 19 (RIA Novosti) - Russian police and Federal Security Service officers have killed three militants in Dagestan's Kizlyar District, a spokesman said Saturday.

"The officers tried to stop a Niva Chevrolet, but three people inside the car opened fire, and were killed by return fire," the spokesman said.

He added that one of the three has been identified as a militant leader, and that police officers discovered an arms cache in the car.

An investigation is underway.

The Russian North Caucasus republics of Chechnya, Dagestan and Ingushetia have seen an upsurge of militant violence of late, with frequent attacks on police.

The Kremlin officially ended its anti-terrorism operation in Chechnya in April. The republic saw two brutal separatist wars in the 1990s and early 2000s.