Ten people were killed when a blast tore through a cafe at a market in Russia's southern Orenburg region overnight, Russian news agencies reported Monday.

"A blast occurred in a cafe next to a local market in the town of Orsk," a spokesman for the emergency situations ministry, Viktor Beltsov, said.

"Ten people died as a result," he said, adding that the building had been completely destroyed by the blast and subsequent fire.

Officials said they were unsure of the cause of the blast but said it may have been intended to cover up a murder.

All 10 victims, apparently including the cafe's owners, were found in one corner of the bar.

Officials told the Vesti television channel that clients at nearby cafes had heard sounds that could have been small explosions or gunshots.

PHOTO CAPTION

File picture of Russian firefighters. (AFP)