Signs have been torn down at the field where tram horses are being kept and debris has been thrown into the enclosure.
Isle of Man Transport came across the issue this morning at the Clypse field after urging the public yesterday not to go near the animals so they can stay safe during the COVID-19 pandemic - two of the horses are heavily pregnant.
The team says cars have also been parking in front of the gates meaning staff can't get into the fields to take care of the creatures.
Officials add whilst they know the area is a popular walking spot, anyone heading down mustn't attempt to touch or feed the horses or come into contact with the field gates.
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