Updated

MOSCOW -- A man blew himself up with a grenade near a supermarket in Moscow on Saturday, Russian news agencies said. No other injuries were reported.

Police had no immediate official comment and reports from unidentified witnesses and police sources gave contradictory accounts of the blast in northeastern Moscow that killed the man. There was no immediate indication of whether the blast was intended as a terrorist act.

The Interfax news agency cited witnesses as saying the man drove alongside a supermarket, got out of the car and went up to the store's entrance muttering unintelligibly, then pulled out the grenade and set it off. Other reports said he was either in the car or next to it.

A suicide bomber killed 37 people in a Jan. 24 blast at Moscow's Domodedovo airport, the country's busiest. A leader of Islamist insurgents in Russia's Caucasus claimed responsibility for ordering that attack.