Nine people were killed and more than 100 were injured when two passenger trains collided head-on near a Bavarian spa town about 60 km (37 miles) southeast of Munich on Tuesday, German police said.

Among the 108 people injured, 18 were in a serious condition, after the crash at a peak commuter time of 6.48 a.m. (0548 GMT) near Bad Aibling in the southern state of Bavaria near the border with Austria. One of the trains was derailed.

Dozens of rescue teams were on site and helicopters took some of the casualties to nearby hospitals. The area was sealed off and alongside the rescue effort, a crash investigation had begun, police said.

The trains' operator, Meridian, is part of French passenger transport firm Transdev, which is jointly owned by state-owned bank CDC and water and waste firm Veolia (VIE.PA).

Transdev said in a statement that management and staff were terribly shocked by the "exceptionally serious accident" and that Chief Executive Jean-Marc Janaillac was at the scene.

German Transport Minister Alexander Dobrindt, also at the site of the crash, said it was unclear whether it had been due to a technical failure or human error.

State-owned Deutsche Bahn is responsible for the track. The line has a system that makes a train brake automatically if it goes through a red light.

Police will hold a news conference but it was delayed from the planned 12.00 local time (1100 GMT).

Meridian runs train, tram and bus networks in 19 countries and had revenues of 6.6 billion euros ($7.4 billion) in 2014.