Leading candidate Henriette Reker.

A leading candidate to be mayor of Cologne has been wounded in a knife attack as she campaigned a day before an election in the western German city.

Candidate Henriette Reker was stabbed in the neck in the attack at a market yesterday morning, the city government said in a statement. It said her life was not in danger, as did Ms Reker’s campaign team.

Four other people were wounded, one of them seriously, in a scuffle as they tried to overwhelm the suspected attacker, who was then arrested. There was no immediate word on his possible motive.

The attack happened as Ms Reker was visiting a campaign stand set up by Chancellor Angela Merkel’s Christian Democrats.

Ms Reker, 58, is running as an independent candidate in today’s election but has the backing of the conservative Christian Democrats and two other parties. She has been the head of the city’s social affairs and integration department since 2010.

Outgoing mayor Juergen Roters said he was “deeply shocked” by the attack. Centre-left Social Democrat Jochen Ott, Ms Reker’s main rival in the election, suspended his campaign.