Four people were arrested in the Bethesda area this week by police sent to stop an unusual surge in thefts from cars there, authorities said.

About 45 cars were entered in recent weeks in southwestern Montgomery County, near River Road, and items were taken from many, county police said. It was a significant outbreak of a type of crime that has plagued the entire Washington area.

At least a half-dozen thefts from cars were reported this month in Alexandria; another half-dozen were reported in one overnight period this week in upper Northwest Washington.

On Thursday morning, Montgomery police said, officers in the area of the Bethesda thefts stopped a suspicious vehicle. Police said the vehicle held items thought to have been stolen. Four people, none older than 20, were arrested, and charged with possessing burglar tools with the intent to enter a car, police said.

Police urged that cars be locked and valuables and keys be removed or placed out of sight.