Seven students at two Washington public high schools were escorted from their classes by school officials yesterday morning and turned over to D.C. police who charged them with selling phencyclidine, a drug commonly known as PCP, according to school and police officials.

The arrests, which followed a four-month investigation aimed at curbing drug abuse among students, were made after undercover police officers posing as students allegedly purchased a "considerable amount" of drugs from the suspected PCP dealers, police said.

Six students were arrested at McKinley High School, Second and T streets NE, and a seventh student was arrested at Cardozo High School at 13th and Clifton streets NW.

Four of the students, all McKinley seniors, were 18 or older and have been charged as adults with selling PCP within 1,000 feet of a school, police said. They were identified by police as Kevin Harrison, 18, of 1839 24th St. NE; Major H. Unger, 19, of 111 Franklin St. NE; Guy M. Johnson, 18, of 228 Hamilton St. NW, and Gregory M. Stallings, 18, of 4907 12th St. NE. If convicted, each faces a maximum of 30 years in jail.

The three students under 18 were charged as juveniles with selling drugs, police said. Two were released to their parents and the third was sent to the city's Receiving Home for Children.

Police said the investigation was started at the request of school safety and security aides who had identified suspected drug dealers at the schools. School Superintendent Floretta D. McKenzie knew about the investigation and ordered school employes to cooperate fully with police, according to school spokeswoman Janice Cromer.

School administrators and security officials said investigations are being conducted at several other high schools in the city, but refused to name the schools.

McKenzie "has always promised to take a very hard line against drugs in the schools. She wants to make the schools drug-free," said Cromer.

McKinley Principal Bettye Topps said the arrests "should send a clear signal to students who may be involved in drugs or thinking about getting involved. There is a penalty for such actions."

Topps said police arrived at McKinley about 9 a.m. with arrest warrants. Students arrested were escorted from their first-period classes and taken out of the school "discreetly" through a side door of the building, she said.

Topps said she has warned suspected drug dealers to stop because "something bad was going to happen to them if they didn't. Well, it happened today. I'm sure police have undercover police in every school because the superintendent has made fighting drugs a high priority."