One of Russia's most prominent reputed crime bosses was shot dead on a street in central Moscow on Wednesday, law enforcement officials said, less than three years after he survived an assassination attempt.

An unidentified gunman shot Aslan Usoyan, 75, known in the underworld of the ex-Soviet Union as "Grandpa Hassan", and he died shortly afterward in hospital, the federal Investigative Committee said. A woman suffered two gunshot wounds.

Usoyan was shot outside a restaurant by a sniper, the Interfax news agency reported, citing an unidentified official. News site lifenews.ru, which has ties to law enforcement agencies, said the sniper fired from a rooftop.

The Investigative Commitee said they were looking into potential motives for the killing, including links to his criminal activities, but declined to give details.

Usoyan was first convicted at age 19 and served multiple jail terms in the Soviet era, including for refusing to obey police, theft and "speculation" - illegally trade that was under close scrutiny in the communist Soviet Union.

He earned the underworld title of "vor v zakone" - or thief in law - meaning a criminal godfather.

During the chaos which accompanied the 1991 fall of the Soviet Union there were almost daily killings across Russia as criminal gangs battled to gain control of lucrative businesses and carve up territory.

According to Russian media reports, in the years after the Soviet collapse he headed an organised crime network involved in illegal gambling, drugs and arms sales and natural resources extraction.

Usoyan survived an attempt on his life in September 2010, when a hitman shot him in the stomach as he got out of his car near the Kremlin. Media reports at the time linked that shooting to a turf war.

Usoyan's killing echoed that of criminal boss Vyacheslav Ivankov, known as Yaponchik, who served a prison term in the United States on extortion charges. He was shot by a sniper in July 2009 outside a Moscow restaurant and died three months later.