Updated 2.45pm
Firefighters were called to Santa Venera at lunchtime on Monday following reports of a fire close to the former St Philip's hospital.
The Psaila Street fire, which was reported at 12pm, broke out inside a room built above an electricity substation.
A Times of Malta reader sent a video of a billowing cloud of smoke in the area.
Members of the Civil Protection Department quickly put out the blaze before anybody was hurt.
Footage sent in by Times of Malta reader.