Two men were shot and killed last night in Prince George's County as they sat inside an automobile near a busy intersection, county police said. A third man was wounded in the attack.

The shooting occurred about 10 p.m. in the 5600 block of Quintana Street, in the Riverdale Heights area, according to Cpl. Clinton Copeland, a county police spokesman.

The motive in the shooting, which occurred as the men sat in a Toyota, remained unclear early this morning, Copeland said. He said it had not been determined how the assailants fled, by car or on foot.

He said police were looking for three or four men in connection with the shooting, which appeared to be one of the deadliest in the county in recent weeks.

The site of the shooting is within two blocks of the intersection of Kenilworth Avenue and East West Highway, two of the major arteries in the northern part of Prince George's.

The neighborhood around the intersection had seemed largely free of the upsurge of violence that has engulfed other areas of the county that lie within the Capital Beltway.

A resident of the area said he was surprised when told that gunfire had erupted in the neighborhood.

"It's the first time I've heard anything" like that, said Bruce Woolner.

He called the neighborhood peaceful and said, "The only loud noises I hear around here are on the Fourth of July."

Police tape wound around the site of the shooting late last night, and investigators remained at the scene.