Peter Cushing, Metrolink Director at TfGM, said: "Late last night vandals damaged both a tram and the tracks near the St Werburgh's Road tram stop. This has led to one tram being damaged and another being stuck, blocking the tracks on the Airport and East Didsbury lines.
"Technicians have been on site since first light to start to move the tram and repair the tracks. However, because of the nature of the damage caused, we do not know how long this will take.
"In the meantime, passengers can use their tickets on alternative bus routes and get the latest information from the Metrolink website and Twitter feed.
"I'm disgusted by the behaviour that we saw last night and we will be working with the police to help them with their enquiries.
"I'd like to apologise to our passengers for the disruption caused by the vandalism, and reassure them that we are working as fast as we can to get all services running again."
More top news
The family of a baby girl who died after she was taken to hospital from a flat in Radcliffe have spoken of their heartache.
Attacker escapes before police arrive
Charity match to raise funds for a new club for next season