The Islamic leader of Tatarstan, Russia's largest Muslim region, was wounded and his deputy was killed on Thursday in two separate attacks, investigators said.
The Mufti of Tatarstan, Ildus Faizov, was wounded in a car explosion while his deputy Valiulla Yakupov was shot dead in front of his home in rare attacks in the historically Muslim central region.
"A criminal case has been opened into murder," Russia's Investigative Committee said in a statement, saying that Yakupov, 64, was shot on the porch of his home and died from his wounds in his parked car.
Faizov was wounded in an explosion that went off as he got into his car to go to work, a spokesman for investigators in Tatarstan told the Interfax news agency.
"An explosion went off at this time. Faizov was thrown back by the explosion and he was wounded. He is currently hospitalised," a senior aide to Tatarstan's chief investigator, Eduard Abdullin, said.
Tatarstan is touted by Russia as an example of peaceful coexistence of Muslims and Christians, in contrast to the troubled North Caucasus, and has been visited by leaders including US Secretary of State Hillary Clinton.