At midnight, the night before Sunday, the rescue service was alerted to a parking lot in Nyfors in Eskilstuna.
There it burned in two vehicles and a third is said to have been damaged by the fire.
According to the rescue service, the fire was soon under control.
A little later in the night, the rescue service was alerted to another car fire in a parking lot.
This time on Oppundavägen in Katrineholm.
On the night before Good Friday, Katrineholm was hit by several other car fires that the police suspect were started.