Tram services in the city centre were suspended this evening after a window pane fell from a building on to a stretch of track.
Police taped off an area near to Piccadilly Place on Sunday afternoon.
Eyewitnesses reported seeing a shattered pane of glass on the tram tracks running between Aytoun Street and Piccadilly station.
Pictures from the scene also show a damaged window on the sixth floor of a nearby office building.
For a short time no Metrolink services were running between Piccadilly and Piccadilly Gardens as a result of the incident.
Metrolink tweeted: "Due to a police incident in the City Centre, Ashton services are currently operating Ashton-Piccadilly only and Eccles services operating Piccadilly Gardens-Eccles only.
"There are no services between Piccadilly and Piccadilly Gardens.
"Please check back for updates."
Metrolink later confirmed the line had reopened.
Greater Manchester Police have been contacted for further information.
