"Eduard Chuvashov was murdered today," the spokesman said, declining further detail.

Investigators said he was shot in the chest and head at 8:50 local time (0450 GMT) and died on the spot, according to Russian Prosecutor General's site sledcomproc.ru.

Possible links between his work and his murder are being examined, they added.

Neo-nationalists could be behind the attack, Interfax news agency reported, citing an unnamed law enforcement source.

Local media said Chuvashov was the judge who had sentenced 12 ultra-nationalists from the Russian fascist group known as the "white wolves" in February.

Mostly teenagers, the group were found guilty of a string of brutal murders against dark-skinned migrants from Central Asian countries, many of whom had been bludgeoned to death.

SOVA, a non-governmental organization that tracks racist violence in Russia, says at least 60 people were killed in Russia last year in hate crimes, and 306 were injured.