State troopers using a helicopter and police dogs were searching last night for seven of nine teen-age boys, described as "hardcore" offenders, who escaped from the Charles H. Hickey Jr. School by crawling through a broken window, officials said.

The boys broke out about 8:30 p.m. and ran into nearby woods, state police said. State police said juvenile justice officials discovered the escape during a routine check of the boys' rooms and noticed the broken window. There were conflicting reports last night about whether the boys scaled a tall fence topped with barbed wire or cut through it.

The boys should be considered dangerous, said police, who warned people to use caution if they see them.

"They are hardcore and high-risk" offenders, said Lt. Raymond Grissett of the Golden Ring barracks, whose troopers were leading the search.

It was unclear where police were concentrating their search early this morning. No police or security patrols were apparent near the Hickey School.

State police used a helicopter at the start of the search but had to send it to another emergency. They were using police dogs to track down the teen-agers.

About an hour after the escape, troopers caught two 16-year-old boys near Gun Hill Circle and Parkfalls Road, about two miles from the school, police said. Troopers initially focused their search for the remaining escapees in nearby woods.

Police said the boys were wearing white shirts with "Hickey School" emblazoned on them and gray pants. It was not clear last night why the teen-agers were being held at the Hickey School, a maximum security facility for juvenile offenders in Carney.

State police referred all other questions to juvenile justice authorities, who could not be reached for comment last night.

Local residents said they were surprised by the escape. One woman said she was eating ice cream when she heard a helicopter flying over her house on Powderhorn Lane.

Another received a recorded telephone message from the school warning residents about the escape and saying that authorities were trying to find seven boys. She was told to turn on her home's lights and to call police if they see any of the boys.

Catia Petronelli, who lives near the school, heard about the escape from her nervous husband, who called her. She said her parents, who also live nearby, came over about 10 p.m., because they were worried about the escapees.

It was not the first breakout from the Hickey School this year. In January, two teens escaped from a transportation van as it approached Hickey after the boys appeared in court. Last year, two boys broke out of the school's infirmary.

Hickey is one the state's three largest juvenile facilities, which are home to hundreds of the state's male teen-age offenders.