A man has been arrested after injuring seven people at Dusseldorf's main train station, German police have said.

"A person, probably armed with an axe, attacked people at random," police said in a statement after Thursday's attack.

Three of the injured were in serious condition.

The suspected attacker was arrested after jumping off an overpass near the train station, the statement said.

The 36-year-old man, described as being from "the former Yugoslavia" and living in the nearby city of Wuppertal, suffered serious injuries and was being treated in a hospital.

"The suspect appears to have had psychological problems," police said.

Previously police had said several attackers were involved and two were arrested but they later said one suspect was behind the assault.

"We are not using the words 'rampage' or 'terror'," a spokesman said.

Heavily armed special forces evacuated the station, which was cordoned off, while train services were cancelled or rerouted.

Police said an axe was recovered and officers were searching the area in and around the station.