A prominent Muslim figure who pledged to "cover Moscow in blood" if the authorities refuse to establish Islamic law has fled Russia, the BBC Russian service reported on Friday, citing an activist group.

Dagir Khasavov fled to a "European country" after receiving threats, the Russian Political Emigre Society said.

Prosecutors said on Thursday they saw "calls for extremism" in a televised interview earlier this week in which Khasavov, a lawyer and aide to an upper house committee chairman, said any attempt to stop the introduction of a system of Shari'a courts would "result in blood."

"We will turn [Moscow] into a second Dead Sea," Khasavov told the REN TV channel.

Russia's Chief Mufti Talgat Tadzhuddin has condemned Khasavov's remarks, and liberal opposition party Yabloko leader Sergei Mitrokhin asked prosecutors to bring extremist charges against him.

The Federal Lawyer Chamber has called for his licence to be revoked.

Khasavov has said his remarks were misunderstood.

His son, Arslan, said his father has been made a "scapegoat."