MOSCOW (AP) — A top Muslim cleric in Russia’s Tatarstan province was shot dead and another was wounded by a car bomb in two attacks that local leaders said were related to the priests’ criticism of radical Islamists, investigators said Thursday.

Valiulla Yakupov, the deputy to the Muslim province’s chief mufti, was gunned down Thursday as he left his house in Tatarstan’s regional capital of Kazan, Russia’s Investigative Committee said. Minutes later, chief mufti Ildus Faizov was wounded in the leg after an explosive device ripped through his car in central Kazan, it said.

Both clerics were known as critics of radical Islamist groups that advocate a strict and puritan version of Islam known as Salafism. Investigative Committee spokesman Vladimir Markin told Russian news agencies that his agency was looking into the clerics’ professional activity as a possible reason for the attacks.

The 49-year-old Faizov became Tatarstan’s chief mufti in 2011 and began a crackdown on radical Islamists by dismissing ultraconservative preachers and banning textbooks from Saudi Arabia, where the government-approved religious doctrine is based on Salafism.

He has also been criticized by media in Tatarstan for allegedly profiting on tours he organized for Muslim pilgrims and for trying to gain control of one of the oldest and largest mosques in Kazan that receives hefty donations from thousands of believers.

The rise of Salafism in this oil-rich Volga River province has been fueled by the influx of Muslim clerics from Chechnya and other predominantly Muslim provinces of Russia’s Caucasus region, where Islamic insurgency has been raging for years.

In 2011, Doku Umarov, leader of embattled Chechen separatists, issued a religious decree calling on radical Islamists from the Caucasus to move to the densely-populated Volga River region that includes Tatarstan and other provinces with a significant Muslim population.

Former separatists and Islamic radicals from the Caucasus have called for the establishment of a caliphate, an independent Islamic state under Shariah law that includes the Caucasus, Tatarstan and other parts of Russia that were once part of the Golden Horde — a medieval Muslim state ruled by a Tatar-Mongol dynasty.

Thousands of their supporters in Tatarstan, including members of Islamist youth groups, wear clothes and beards associated with Salafism.

More than a half of Tatarstan’s 4 million people are Sunni Muslims. Tatars converted to Islam more than a thousand years ago, and the province became an important center of Muslim learning and culture under Tatar-Mongol rulers who controlled Russia and parts of Eastern Europe.

Tatarstan’s regional leader condemned the attack and called for tougher measures against radical Islamists.

"What happened today is an obvious challenge," Rustam Minnikhanov was quoted by the Interfax news agency as saying. "Our position must be much tougher. Traditional Islam has never allowed such things" as the attacks.

A Muslim leader from a neighboring region blamed local authorities for failing to thwart the assassination on Faizov by Islamic radicals. Muhammedgali Khuzin, mufti of the Perm region, told the Interfax news agency that he submitted a report in April to regional authorities about dangers related to the emergence of radical Islamist groups.

"No due security measures have been taken," Khuzin was quoted as saying.

In 2008, a court in Kazan sentenced a radical Islamist leader to life in prison for organizing a group that planned terrorist attacks in Tatarstan. Sixteen of his followers received prison terms ranging from three to 12 years.

Moderate Muslims and officials in Tatarstan have long been concerned about the growing influence of radical Islamists. An anti-terrorism drill for local law enforcement officers will take place later this month.