SALINA, N.Y. — A double-decker bus hit a railroad bridge in central New York and flipped over on its side early Saturday, killing four people and injuring numerous others, some critically, authorities said.

The bus was carrying at least 20 people when it crashed on the Onondaga Lake Parkway in Salina, a Syracuse suburb, around 2:30 a.m., said Larry Ives, supervisor of dispatch operations for the Onondaga County Sheriff's Department.

He said the bus was too tall to make it under the low-clearance bridge.

Ives confirmed that four people were killed and numerous others were taken to hospitals with injuries ranging from critical to minor.

The Megabus left Philadelphia at 10 p.m. Friday and was headed for Toronto with stops in Syracuse and Buffalo, said Don Carmichael, a senior vice president Coach USA, which operates Megabus.

He said the bus was off its route when it crashed but he didn't know why.

The crash shut down the Onondaga Lake Parkway.