A Ford Ka and a Fiat Panda parked outside separate addresses in Burnside Terrace in Fauldhouse, West Lothian were targeted by criminals trying to steal fuel overnight between last Wednesday and Thursday.
The Punto had its brake line cut, while the other vehicle sustained damage to the fuel line, which resulted in petrol leaking onto the road.
Both owners took their cars to mechanics who this week confirmed the damage and police were contacted.
A police spokesman said: “Not only have these incidents resulted in damage to both vehicles, but those responsible could have ensured that the victims or other members of the public suffered serious injury as a result.
“Anyone who remembers seeing anything suspicious in or around Burnside Terrace between Wednesday and Thursday last week is asked to contact police immediately. Similarly, we are also keen to hear from anyone who can assist us in identifying these suspects is also asked to get in touch.”