PORTLAND — Portland police are urging residents to lock their cars and hide valuables after a string of car break-ins that exclusively targeted unlocked cars.

Portland police assessed the rash of car burglaries as part of the department’s weekly CompStat process. The statistical analysis showed that all 14 car burglaries reported last week were into unlocked cars, where iPods, sunglasses, compact discs and change were stolen.

“It is certainly a crime of opportunity,” said Detective Sgt. Dean Goodale. “If they see it and the doors are unlocked, they’re going to take it, or if they see the door is unlocked, they’ll look for it.”

Those burglaries were not concentrated in any one area of the city and probably involved different thieves, police said.

The final two weeks of October did see a cluster of car burglaries in the University of Southern Maine area bounded by St. John Street, Forest Avenue, Noyse and Washburn streets. Those 13 cases included two cases where someone entered an unlocked garage and then an unlocked car, technically a home burglary, which is a felony.

There have been 590 vehicle burglaries so far this year compared to 665 last year, police said.