SOFIA, Bulgaria (AP) — A bus crash in western Bulgaria early Tuesday morning has killed at least 45 people, authorities say.

The bus, which was registered in Northern Macedonia, crashed around 2 a.m. and there were children among the victims, authorities said. Seven people were taken to hospitals for treatment.

Bulgarian news agency Novinite says representatives from Macedonia’s embassy visited a hospital where some of the victims were taken.

The cause of the crash was not immediately clear.