Dmitry Fotyanov was shot around noon Wednesday in Dalnegorsk, about 5,750 miles east of Moscow. Police said attackers used an assault rifle equipped with a silencer, Russian media reported.
Russian news reports said the gunmen were riding in a car that later exploded, but it was unclear precisely when the explosion occurred or whether there were any injuries from the blast.
Investigators were focusing on whether the killing was to keep Fotyanov out of a runoff election scheduled for next week, said Irina Nomokonova, an official with the Primorky Krai regional prosecutor's office.
Russia has seen a rash of high-profile murders in recent weeks, including the killings in Moscow of a top Central Bank inspector and investigative reporter Anna Politkovskaya.
While on a lesser scale than in the turbulent 1990s, contract killings still occur regularly in Russia, where business conflicts often turn violent and the government is seeking closer control over economic activity. The murders are almost never solved.