MOSCOW (AP) — A gunman opened fired at a bus and a bus stop in central Russia on Monday, killing three people and wounding three more, police said.

The shooting took place in a village in the Nizhny Novgorod region located around 400 kilometers (about 250 miles) east of Moscow. Police said the man escaped and urged local residents to be cautious since he was armed. A major manhunt was underway and a murder investigation was launched.

The motive for the shooting hasn't been revealed, but Russian authorities haven't indicated the shooting was terror-related.

Three men died and three women were hospitalized with gunshot wounds, according to Russia’s Investigative Committee. Local officials said two of them were in extremely grave condition.

Some media reports said the assailant wasn't aiming at the bus, but rather fired random shots at people at the bus stop.