An 18-year-old woman was shot and seriously wounded by D.C. police yesterday in a chase that began when she reportedly shot a security guard in a downtown store in the leg after he tried to question her about some items she carried in a shopping bag.

The suspect ran from the Woodward & Lothrop store at 11th and F streets NW about 7 p.m. and forced the woman driver of a passing car to take her on a high-speed chase along several downtown streets, police said. Police joined the chase being summoned by store guards.

As police cars followed, the frightened driver, who was not identified, suddenly swerved off Third Street NW between E and F streets into a parking lot only two blocks from police headquarters. Then she ran for safety.

With police closing in, the suspect jumped from the car and ran into the middle of Third Street, firing at least one shot toward pursuing officers, police said.

Three of the officers returned fire, striking the woman several times, police said.

Both the suspect, whose identity was not disclosed immediately by police,and the injured security guard, identified as John Cooper, were taken to George Washington University Hospital.

The woman was listed in serious condition. Cooper was said to be in satisfactory condition.

Police said the incident began just before the store was to close at 7 p.m. after one of the security guards on the third floor of the store's south building reported he had seen a woman acting suspiciously while carrying a shopping bag containing some items.

Police said three security guards on the scene followed the woman into an elevator and attempted to question her. It was then, they said, that she produced a pistol and fired once at the guards, striking Cooper.

Leaving the elevator, the woman fled from the storeand jumped into the passing car, police said.

Police identified the three police officers involved in the caseas George Hardy, Roland Swinger and Frank Strother.