NEW YORK (DPA) - A man shot and killed four of his neighbours in an apartment building in Chicago on Saturday night (Oct 12), according to police.

The man also seriously wounded one person in another apartment in the same North-west Side building, said police in the central city.

"Suspect in custody is a neighbour who is known to victims," said Chicago police on Twitter.

It is not clear how the gunman got into his neighbours' apartments.

The shooting had occurred at 5.30pm. Police were investigating, and a weapon has been recovered from the scene.

Deputy Superintendent Anthony Riccio of the Chicago Police Department told local media that there was no clear motive as of yet, but that the man had had run-ins with neighbours in the past.

Chicago Mayor Lori Lightfoot mourned the "mass shooting at a condo building" on Twitter on Saturday and said she would continue working to take "guns out of the hands of those who are mentally infirm".