Prince George's County school officials say they are stunned by a report showing a 30 percent increase in crime in county schools, and the new head of the Board of Education called the statistics "disappointing and alarming."

Crime committed by students -- from physical assaults to clothing and shoe thefts -- rose during the 1989-90 school year to 1,929 incidents, up from 1,490 reported the previous year, according to a report released late last week by the school system's Department of Security Services. Assaults and thefts accounted for 60 percent of the increase.

The annual report also indicated that the school system's crackdown on drugs continues to show good results, with 30 cases reported last year, down from 34 the previous year. During the 1984-85 school year, schools were overrun with drug activity, with 204 reported drug-related incidents.

Still, school officials found little good news in the report. "This is disappointing and alarming," said Catherine Burch, who took over Monday as board chairman. "The school system will have to play the role of parent and try to do something about this."

Peter Blauvelt, school security director, said that "aggression has become an absolutely acceptable act for getting out your feelings. Even in watching kids play today, it is a much more aggressive competitive play."

The county's 114 elementary schools carried the brunt of the increase, reporting 495 incidents of student misconduct, 175 more than the year before. Middle school crime was up by 148 incidents to 452. High schools saw their crime rate go up by 115 incidents, to 958.

The incidents resulted in 831 arrests.

"The students are simply are mirror of society as a whole," said Marshall Sterling, principal of Suitland High School.

The numbers alarmed school officials who had been touting a student crime rate that had declined in the past decade, from 5,600 offenses in 1980 to 1,400 last year.

Blauvelt said the figures do not include those incidents school officials were able to resolve at the individual school.

Blauvelt said that shutting down smoking areas, where he said students often congregated to sell or use drugs, and stiffer penalties against students caught with drugs contributed to the decline in drug-related incidents. Students now face expulsion if found distributing drugs at school.

Student possession of weapons remained the same, with the system reporting 122 cases of students carrying weapons to school. Twelve of the incidents involved firearms. The others involved knives, and BB and pellet guns.

School board member Brenda Hughes said she was surprised by the increase, and questioned whether school security investigations were thorough enough.

"A lot of this is just not investigated very well, we need to look at the underlying causes for the increase . . . or it will escalate," she said.

Last month, three Suitland High School students testified at a school board meeting that they had been physically assaulted and harassed by other students. One student, Danielle Gillette, a junior in Suitland's arts magnet program, said she was hit in the head and kicked by a fellow student during a pep rally.

The three students, who are white, said the incidents, which they said were perpetrated by black students, show that more needs to be done to quell the tension between students of different cultures.

Board Vice Chairman Sarah Johnson said the board would study the report to look for those schools with the highest increases and target them for extra security officers and other measures.