A teenage girl was attacked and killed last night in a Montgomery County high school parking lot after a football game, police said.

The 15-year-old was attacked about 8:30 p.m. outside James Hubert Blake High School in the Norwood area of northeastern Montgomery.

Police said they did not know how she was attacked, saying that reports conflicted. A school system spokesman said she had been stabbed.

Lt. Eric Burnett, a spokesman for the Montgomery County police, said a large fight apparently broke out after the game. It involved mostly or exclusively girls, he said.

Police did not release the slain girl's identity yesterday, and it was not clear whether she attended either of the schools that played last night, Blake and Sherwood High School, said Brian Edwards, a spokesman for Montgomery public schools. He said she might have been a student at another county school.

Police said they believed the fight involved students from the Silver Spring and Rockville areas. They reported no arrests and said the motive for the fight was not immediately clear.

"We don't know what set this off," Burnett said.

"I do not believe it was related to the game," Edwards said.

Blake lost the game, its third of the season, 44-0. Blake, a relatively new school, opened in 1998 and is on Norwood Road, about four miles northeast of the Glenmont terminus of Metro's Red Line.

A witness interviewed last night said he saw a group of people surrounding a sport-utility vehicle. They banged on its windows and yanked on the doors, trying to pull out the occupants, he said.

The man said he saw the 15-year-old, who he believed had been in the vehicle. "They were banging on the car, and the girl was terrified," he said.

Rescue squad personnel said it appeared that the girl had suffered one or more chest wounds, authorities said.

A teenager said her cousin, a student at Sherwood, suffered a cut finger in the fight.

Police cordoned off the area with yellow plastic tape, but people nearby saw youths standing or sitting in ones and twos, with police interviewing them.

There was no indication last night of any gang involvement in the slaying.

Two students were stabbed this summer after classes at Springbrook High School, also in Montgomery. The same day, teenagers were stabbed at a Target store in Wheaton.

School administrators have ratcheted up efforts to ensure school safety in the county and said they would have a police officer at every high school this year.

In June, a recent Damascus High School graduate was fatally stabbed in Montgomery after he stepped outside during a birthday party.

Violence involving groups of girls, once almost unknown, has increased in the Washington region in recent years, law enforcement officials have said.