A woman was shot and fatally wounded at the wheel of her car in Southwest Washington last night and the vehicle, out of control, rammed into a church where 300 persons were attending a revival service.

The victim was tentatively identified as Mary Jackson, 37, of 2415 14th St. NE, a supervisor with the Metrorail system. She was shot at least once in the head about 8:15 p.m. at Delaware Avenue and I Street SW.

A church member who was playing the piano during the revival at the Friendship Baptist Church reportedly saw the approaching headlights of the victim's car and bolted from his bench.

The car crashed into a corner of the 15-year-old brick church at 900 Delaware Ave. SW, narrowly missing the sign holding the church bulletin, according to William T. Ferguson, a church trustee.

"It would have come inside the church had it been a little more to the right," Ferguson said.

The vehicle, which apparently had been eastbound on I Street, knocked over a small tree and tore up shrubbery before striking the church. The extent of damage to the building, which can seat 1,500 persons, was not immediately clear. Most persons in the sanctuary at the time of the incident appeared unaware of what had happened.

Little information about the shooting was available early this morning. Police said they had no motive and no suspects.

Investigators reported that two woman's purse had been recovered but declined to say whether they suspected robbery may have been a motive.

Two passersby reportedly heard two or three shots just before the car rammed into the church. Persons who went to the scene said they believed the woman had been shot in the neck as well as the head.

The woman was pronounced dead at George Washington University Hospital, where she was taken by a fire department ambulance. One fire official said the woman's head wound was in the left temple, suggesting that someone may have shot from outside of the auto.

No other injuries were reported in the incident.

Mary Jackson was identified by Metro officials as a "line" supervisor, who had responsibilities that took her throughout the Metro subway system.

They said that she was scheduled to complete her work shift yesterday at 1:30 p.m., and would have been off duty at the time of the shooting.

Relatives said Jackson was the mother of six children and had worked for Metro and its predecessors for about 10 years.

They said she had been assigned yesterday to the National Airport station on Metro's Blue Line. Shortly before the shooting, they said, she had been visiting a friend in Southeast Washington. One witness said she was wearing her Metro uniform when shot.

Relatives recalled that one of the woman's children, Eric Jackson, had been shot fatally in an earlier incident.

Eric Jackson, 18, was shot Dec. 30, 1976, after a fight at a dance at a church on North Capitol Street.