The Alexandria Police Department, moving to shore up drug enforcement efforts after Police Chief Charles T. Strobel's departure under fire, is assigning 10 additional officers to crack down on drug traffic in poor neighborhoods.

In a related move, the City Council last night unanimously passed a resolution declaring drug enforcement to be the city's top priority.

City Manager Vola Lawson and police officials told the council that, effective immediately, every member of the department's vice and narcotics squad will be assigned to street details during the evening, when drug markets are most active.

The reassigned officers will combine with the department's seven-member tactical squad, which targets drug-plagued neighborhoods in the same manner as the District of Columbia's Operation Clean Sweep, raising the total number of Alexandria officers concentrating on drugs to 17.

This arrangement will continue, Acting Police Chief Arlen Justice said in a memo to Lawson, "until existing conditions dictate change. I expect this coordinated effort to make a major impact on drug traffic in our most troubled neighborhoods."

City Council member Carlyle C. Ring, who heads a task force on drugs, said, "Lawless elements have literally taken over some of our neighborhoods. We have residents who are afraid to go out of their homes at night. It amounts to a crisis."

The change in police assignments is part of a major shake-up in the department's drug enforcement efforts that began last Wednesday when Strobel stepped down, citing job-related stress, and the commander of the vice and narcotics unit, Lt. Arthur L. Bratcher, was stripped of his command.

An internal probe that was concluded the same day criticized the two men for failing to investigate charges of misconduct against a former narcotics officer. Also, the investigation found that only two members of the vice and narcotics squad were actively investigating drug trafficking.

Lawson called the findings "intolerable" and "a significant failure of top management in the Police Department."

Police Capt. Larry Brohard, who discussed the increased drug enforcement efforts with the council, said the changes were made "because we have a serious problem and that's the kind of resources that are necessary to address it. We're going to put everybody in there that we can."

Brohard said that most of the city's street drug trade is concentrated in two predominantly poor neighborhoods: Arlandria, just south of Arlington, and in a public housing complex near the Charles Houston Recreation Center, just north of Old Town. He said most of the enforcement efforts will be directed at those areas.

In recent weeks, the situation near the Houston Center has been particularly volatile. Members of the tactical squad have made several drug-related arrests there and have sometimes stirred hostility among local residents. A week ago, nine people were arrested for throwing stones and bottles at police cars after arrests were made.

The Houston Center neighborhood is predominantly black, and all of the members of the tactical squad are white. Lawson and several council members have expressed concern that the squad's lack of black members could create problems in the neighborhoods where they work.

Brohard said that while police are concerned about the rock-and-bottle-throwing incident, he believes that neighborhood residents generally support police efforts to crack down on drug sales. "Sometimes arrests like this draw a big crowd, but very few people get involved with the police," he said.