Nine teenage inmates face assault and destruction of property charges following a late-night brawl at a Rockville youth detention facility in which one staff member and seven juveniles were injured, authorities said yesterday.

The Tuesday night disturbance at the Alfred D. Noyes Children's Center resulted in $5,000 worth of property damage and led to a three-hour standoff with police officers when 27 male teenagers, ages 14 to 18, barricaded themselves inside one of the common living areas, authorities said. The confrontation ended after officers persuaded the youths to open the doors and come out.

Police said the incident began when a "play fight" got out of hand, escalating into a melee. One counselor was punched in the face as he tried to break up the fight, and the teenagers closed the doors when staff members left to seek help, authorities said.

Although the disturbance resulted in injuries that were minor, it focused additional attention on the state's Department of Juvenile Justice, which has been under intense scrutiny in recent weeks after a series of Baltimore Sun articles detailing abuses at a state-run boot camp for juvenile offenders in Western Maryland. Five top officials, including the department head, were ousted in the wake of those reports.

Noyes is one of several juvenile detention centers that have been criticized in recent years by advocates complaining of crowded conditions and lack of mental health, education and other services for young inmates.

Juvenile Justice officials said yesterday that there was sufficient staff on hand for the number of inmates at Noyes on Tuesday night. Six youth supervisors and a nurse were on duty, and the inmate population was 66. The state-rated capacity of the facility is 57 inmates.

Last night, Montgomery County Executive Douglas M. Duncan said the county would increase its monitoring of the state-run facility. The county has had employees from its Department of Health and Human Services monitoring Noyes since Dec. 18, when Gov. Parris N. Glendening (D) asked social service agencies to provide a monitor at juvenile facilities across the state to guard against abuse. Duncan said Montgomery would put a second monitor at Noyes during the evening "to add another set of eyes and ears."

Agnes Leshner, the manager of Montgomery's child welfare services, which has provided the monitors, said they have seen no evidence of abuse at Noyes. But, she added, the center is short of staff and does not provide adequate services for the detainees.

"There are a lot of things that make it a very, very tense situation there," Leshner said. She and others said the holiday season may have contributed to the stress level by adding to the juveniles' sense of confinement.

Others said the disturbance was likely the result of the crowded conditions at Noyes and the lack of sufficient staff and services. "A lot of these kids already aren't happy because of the holidays, then you have these crowded conditions and things are going to turn ugly," said Neil Jacobs, a Montgomery County lawyer who specializes in juvenile cases. "And they don't have the staff to handle it."

Montgomery police spokesman Derek Baliles said police searched the facility, with a dog, and found no weapons.

Bob Kannenberg, a spokesman for the state Department of Juvenile Justice, said the department's inspector general is reviewing the incident. Kannenberg said there was sufficient staff on hand Tuesday night.

Six juveniles were charged with second-degree assault yesterday and three more will be charged later this week, authorities said. One inmate, who is now 18, will be charged as an adult. The teenagers who were being detained in the unit have been placed temporarily in other facilities throughout the system, Juvenile Justice officials said.