Unknown Gunmen seized a bus with about two dozen passengers aboard in Athens suburbs early on Wednesday, CNN reported.

Greek police said the gunmen fired shots at the police who surrounded the bus at a stop 17 km from the city center on the outskirts of eastern Athens.

It was not clear what prompted the seizure.

The bus was on a route from the town of Marathon, east of Athens, to the city center when it was hijacked just before dawn at a stop in the suburb of Geraka.