image sourceAFPimage captionPolice say all those who felt unwell had consumed food or drink from a small kitchen on campus

German police have begun an attempted murder investigation after six people were taken to hospital in a case of suspected poisoning at Darmstadt Technical University.

They had all had food or drink from a small kitchen on the university's Lichtwiese campus.

A "harmful substance" was added to milk cartons or water, police believe.

Investigators have not revealed what type of poison was found but say they know what it is.

The chemical involved is described as having a noticeably "pungent smell".

One 30-year-old student was taken to hospital in a critical condition but the university said everyone affected was feeling better and the last two remaining patients would be leaving hospital later on Tuesday.

Police said at least seven people had displayed symptoms of poisoning and six needed hospital treatment after the tea area in building L2-01 was apparently targeted over the weekend. The area is home to TU Darmstadt's Institute for Materials Science, which includes recycling and reuse of materials.

Investigators warned students who had consumed anything in the building to seek medical treatment if they "feel unwell or their extremities show a bluish discoloration". The seven people known to have been affected had suffered discoloration to their feet and fingers.

The university said it was shocked by the apparent crime that had taken place on its campus and the science minister in the central state of Hesse wished everyone a speedy recovery.

No motive has yet been established and no suspects have been traced.

You may also be interested in

How the world's oldest hat shop made it through lockdown

media caption"We’ve had to dig deep and we’ve had to evolve"