At least 10 people were killed and 41 others injured, including four in critical condition, after a train collided with a double-decker bus at a railway crossing in Mexico State, officials said Monday.

Adrián Hernández, head of the state’s civil protection agency, said the crash occurred when the bus initially stopped at the crossing but then moved forward, only to be struck from behind by an oncoming train seconds later.

Surveillance footage showed the devastating impact as the train slammed into the bus, leaving it heavily damaged.

Authorities confirmed that the bus driver has been detained at the request of the local prosecutor’s office as investigations continue.