At least three people have been killed and several others have been seriously injured after a passenger train derailed in south-west Germany, police say.

Operator Deutsche Bahn said the train crashed at Riedlingen near Stuttgart for "unknown reasons". Reports indicate that a storm had occurred in the area shortly before.

Around 100 people were on board the train when at least two carriages derailed in a forested area around 18:10 local time (17:10 BST), German news agency dpa reported.

German Chancellor Freidrich Merz said he "mourn[ed] the victims" and offered his "deepest sympathy" to their families in a post on X.

He said he was in close contact with the interior and transport ministers and has requested that they provide the emergency services with all the support they need.

In a statement, Ulm police said that current investigations showed "three people were killed and other passengers were seriously injured".

Images of the crash show carriages turned on their sides and a heavy emergency service presence as firefighters and emergency teams worked to gain access to trapped passengers. Fallen trees can also be seen at the scene.

Deutsche Bahn said the train was on a 90 km (55-mile) route between Sigmaringen and Ulm when it derailed.

"The exact situation is still unclear at this time," it said on X. "Our thoughts and sympathies are with the victims and everyone who now has to process this experience."