At least four children have died after a train and a school bus collided in southern France.

The French interior ministry said that seven people aboard the bus were also injured in the accident in the village of Millas, around 15km west of Perpignan near France's border with Spain.

Witnesses said the crossing gates at the scene were working at the time of the crash, with one SNCF railways official saying that the train, which had 25 people on board at the time, would normally travel at 80km per hour.

The official said, according to the Press Association, how witnesses said that barrier was down at the time of the crash on Thursday (14 December) and there would be an investigation to see if the crossing worked properly.

French President Emmanuel Macron tweeted: "All my thoughts go to the victims of this terrible accident and their families. The government is fully mobilised to give them emergency help."

The French prime minister Edouard Phillipe arrived at the scene around 8pm. Shaken, he said the identification procedure of the victims had started and that it was "extremely difficult".

"We understand that they (the families) are going through a time of great anguish," he said, according to France Info, adding that the focus would be an investigation into what happened and helping the families who have been affected.

Meanwhile, Carole Delga, who is president of the Occitan region said that there did not appear to be any mechanical problem. "It would seem that it was well maintained and no sign of failure."

We are thinking of the families whose children have died and about those who are fighting for their lives. It is an appalling tragedy," she said.

France crash
Rescue workers are seen on the site of collision between train and school bus in Millas, near Perpignan, southern France December 14, 2017 in this handout picture. Reuters via France Bleu Roussillon