Two cars were destroyed and another was heavily damaged in a late-night fire in Cospicua.
The police have launched an arson investigation.
The blaze, in Triq Wigi Nosato, appears to have started on a VW Passat. The flames then spread to two cars parked in front and behind it - a Fiat Punto and a Toyota Yaris.
Neighbours tried to extinguish the flames before a fire engine arrived.
Magistrate Tonio Micallef Trigona is holding an inquiry.
Another fire destroyed a car in Sliema while a blaze caused serious damage to the front part of a car transporter in Gudja.