Another Muslim cleric was killed in Dagestan.
Imam Gitinomagomed Abdulgapurov and his bodyguard died in an explosion at the intersection of Shamilya and Chkalova streets in the town of Buynaksk in Russia's North Caucasus republic of Dagestan, a spokesman for the local police said.
Investigators do not know yet what caused the explosion.
For years, Moscow has been fighting Muslim rebels who want to set up an Islamic emirate in the region.
In the past few years, Muslim clerics have been targeted.
In 2006, a virtual assassination campaign was waged against official clerics who opposed local Wahhabists on behalf of the Russian government bent on resisting separatism.
In the North Caucasus, Muslim terrorists tend to carry out targeted rather than mass attacks.
Before the latest incident involving Buynaksk's imam, the deputy mufti of Stavropol, Kurmani Ismailov, was killed on 13 February when a bomb placed under his car exploded.