French authorities on Thursday said a "serious rail accident" occurred in southern France after a regional train crashed into a school bus in Millas, which lies roughly 18 kilometers (11 miles) west of Perpignan.
At least four people dead, including two children, and 19 others injured, according to the Interior Ministry.
"All emergency services have been mobilized and a crisis coordination unit set up," a local official told Reuters news agency. Authorities urged drivers to avoid the route where the accident took place.
Local television showed images of the bus cut in half and the train derailed. The bus was taking children home after school was dismissed, according to police.
French Transport Minister Elisabeth Borne described the incident as a "terrible accident," adding that Paris has already mobilized state services to help the victims.
"All my thoughts for the victims of this terrible accident involving a school bus, as well as their families. The state is fully mobilized to help them," French President Emmanuel Macron said in a tweet.
Interior Minister Gerard Collomb also offered his condolences to the families of the victims.