A 10th-grade student in southern Prince George's County who allegedly attacked a biology teacher with a baseball bat during a class this week faces expulsion and possible criminal prosecution, a school system spokesman said yesterday.

The incident at Gwynn Park High School in Brandywine on Wednesday followed two campus attacks last week in the District. In one, a physical education teacher at McKinley Technology High School suffered a concussion after he was hit on the head by a fire extinguisher dropped from one floor above. In the other, a principal at Coolidge Senior High School was assaulted in a hallway. Two D.C. students were arrested in those cases on suspicion of assault.

The three attacks underscored a reality of campus security as police and education officials seek to protect schools from intruders with deadly weapons: Sometimes, students without knives or guns pose a significant threat to teachers and administrators.

Nationwide, about 4 percent of schoolteachers reported that they were physically attacked by a student during the 1999-2000 school year, according to a survey for the U.S. Department of Education. About 9 percent said students had threatened them with injury. The frequency of reported attacks and threats was higher in central city areas than in rural or suburban areas.

Jerald Newberry, a health expert at the National Education Association, said cash-strapped schools across the country have been forced to cut health and counseling services for students, weakening an important line of defense against students with violent tendencies. Newberry said veteran teachers also report "more aggressive" student behavior than was the norm 15 or 20 years ago.

John Mitchell, who tracks safety issues for the American Federation of Teachers, said violence and threats against teachers did not appear to be rising. But he said some teachers unions have negotiated clauses in their contracts requiring that students who attack a teacher be moved to another school.

"Any one incident is terrible," Mitchell said, "and we need to take strong action when these things happen."

Prince George's schools spokesman John White said the system was taking vigorous punitive steps against the alleged Gwynn Park assailant. He said the principal of the 1,529-student school, William Garrow King Jr., suspended the student and recommended expulsion. White said school officials also had forwarded information to county police for a possible criminal assault charge.

According to White, the male student entered a biology classroom about 1 p.m. Wednesday and allegedly attacked the teacher in front of other students shortly before the class was to be dismissed. A witness said the assailant wore a ski mask, according to the Associated Press.

The suspect had been enrolled in a biology class with the teacher, but not during that period.

White said campus security officers caught the student as he was fleeing the classroom. He was questioned and released to his parents.

White said the teacher was treated at Southern Maryland Hospital Center in Clinton for bumps and bruises, including injuries to the face, head, shoulders and hands. The teacher was released late Wednesday and was recuperating at home, White said.

White declined to identify the student or the teacher. He said the teacher was a 28-year veteran of the school system who had been at Gwynn Park for more than a decade.

"It's unfortunate and unexpected," White said. "It's not a routine occurrence. That's why it's shocking."

WJLA television identified the teacher as Dario Valcarcel, who was listed on a school Web site as a science faculty member.

The school principal did not return a telephone call for comment. Messages left at a residential phone number for Valcarcel were not immediately returned.