AKIPRESS.COM - A regional train and a school bus collided in southern France Thursday, killing four children and injuring more than a dozen other people.

The incident occurred around 4 p.m. local time in the village of Millas. About 20 students between the ages of 11 and 15 were being taken home in a school bus when it collided at a railway crossing with a train, local authorities said in a statement.

French Prime Minister Edouard Philippe, who flew to the scene of the accident, confirmed that four teenage children were killed and 11 others had been critically injured.

"The circumstances of this terrible drama are still undetermined," Philippe said.

A spokeswoman for the French national rail company, SNCF, told ABC News that the train normally travels about 50 miles per hour at the location of the crash and that 25 people were on board at the time. Three of the train's passengers were slightly injured.

An SNCF official told the Associated Press that "several witnesses said the barrier was down" at the time of the crash, adding that the crossing is "well-equipped" with safety precautions, including flashing lights.