A former vice prime minister of Russia's breakaway Chechnya Republic was shot dead early Friday in central Moscow and his wife was seriously wounded, the Itar-Tass news agency reported.

Yakov Sergunin was gunned down by an unidentified assailant at 3:00 a.m. Moscow time (2300 GMT) while walking out of a restaurant with his wife, the agency quoted police sources as saying.

The shooter fired several handgun shots and escaped immediately, riding a motorbike. Sergunin died on the spot and his wife was rushed to hospital and in grave condition.

The authorities has launched a criminal investigation into the murder.

Sergunin served as vice prime minister of Chechnya and chief of staff for the late pro-Russian Chechen leader, Akhmad Kadyrov, in 2001-2003.

Kadyrov, who was elected Chechen president last October, was killed in a bomb attack last month in the Chechen capital of Grozny, baffling the Kremlin's efforts to restore stability and central rule to the war-ravaged region after two separate wars with rebels.

Clashes between Chechen separatists and federal forces continue to claim lives almost on a daily basis and occasionally spill into neighboring regions.