MOSCOW, Dec 7 - A small explosion at a bus stop in central Moscow injured three people on Monday night, and investigators were treating it as an act of hooliganism, Russian news agencies reported.

The blast occurred on Pokrovka street in the Chistiye Prudy part of Moscow, an area that has numerous bars and cafes, possibly after a home-made explosive was thrown from a passing car or nearby building, said Interior Minister spokesman Andrei Galiakberov.

"Three people were injured by shards of glass. Currently, a Moscow police investigative team is working at the scene," Tass news agency quoted Galiakberov as saying.

Galiakberov said the incident was being treated as "hooliganism" under Russian criminal law.

Tass quoted a source in the security services as saying two women had been taken to hospital and a third person had been treated at the scene for minor injuries.