Stepped up enforcement of law and building code violations in a predominantly black section of downtown Alexandria has produced almost 200 arrests since April, but the program's continued success rests on community involvement, Alexandria officials said yesterday.

Public Safety Director Charles T. Strobel, speaking to about 20 members of the Alexandria branch of the NAACP, said enforcement of laws against loitering and drug trafficking in the downtown area divided by Rte. 1 "has a long way to go, but we have come a long way in a very short time."

Since April, Alexandria police have conducted nightly patrols of the 30-block area bordered by First Street, Cameron Street, Columbus Street and the Richmond Fredericksburg and Potomac railroad tracks.

Residents have aided the police effort through surveillance with the Inner City Crime Watch Committee, which was founded in December.

Lt. Earl Walts, in charge of the operation, said officers have arrested 180 to 200 people on charges ranging from loitering to distribution of PCP and have closed seven wine houses, houses or cars where alcohol is sold illegally, in that time.

Several current and former residents who attended the meeting agreed that crime in the area has abated but complained that the police attention was long overdue.

"We must not approach this as something new; it isn't something new," said Fred Day, a former resident of the area, which is represented by the 5,200-member Inner City Civic Association. Crime in the neighborhood "has been a problem which the good people of the 16th census tract have been concerned about for a quarter of a century," Day said.

Another resident expressed concern that heavy police protection of the area might lapse into harassment. The woman, who declined to give her name, said she has been ordered by police officers to move her car when she is merely idling in the street for a few minutes to see if a friend enters the house safely.

Melvin Miller said blacks in the area are too often the target of police suspicion, even when they are doing nothing illegal. "The situation is -- here's a black person sitting in his car double-parked. He must be doing something wrong," Miller said.

City officials urged residents to continue their crime fighting efforts, and both officials and residents stressed that the enforcement program must not lose momentum or it will be nothing more than a temporary patch on a long-standing problem.

"We have made significant inroads but we're not going to stop now," said Mitchell Griffin, vice president of the Inner City Civic Association.

"We're not moving out," Walts said. "We're staying until the civic association is completely satisfied."