District police officers, using an all-but-abandoned city ordinance that bars begging in public, have been arresting abusive and persistent panhandlers for the last month.

The enforcement of the ordinance, which has not been formally announced by the department, was discussed a month ago in a meeting with all District commanders and in theory applies to all areas of the city.

The general counsel for the police department said yesterday, however, that enforcement will be selective, designed to alleviate panhandling in areas where it has become prevalent, where citizens complain and where beggars obstruct passage.

"We don't have the resources to arrest everybody who is panhandling, nor do we wish to," said the general counsel, Geraldine R. Gennet. "What we are doing is proceeding with a legitimate tool, just like arresting for any other offense for which we have probable cause."

Officials did not know the date of passage of the anti-panhandling law, but its wording suggests it was composed decades ago. The ordinance prohibits a person from "wandering abroad and begging, or who goes about from door to door or places himself in or on any highway, passage or other public place to beg or receive alms."

The American Civil Liberties Union is skeptical of the ordinance and will challenge it if it is enforced regularly or if a plaintiff comes forth, said Arthur Spitzer, legal director of the local chapter.

"We just don't think it can be made a crime in this country for one person to communicate peacefully with another on a sidewalk," said Spitzer. "What this does . . . is make it a crime to beg, no matter how polite you are."

The police department did not release any figures yesterday on the number of people arrested. Gennet, who also did not have exact numbers, said enforcement has been limited to the 1st and 2nd police districts, where panhandling is most common. Capitol Hill is in the 1st District and Georgetown is in the 2nd District.

News of the change in policy seemed to catch police officials off guard. The enforcement of the ordinance was first reported yesterday in the New York Times, which said a police captain in the 2nd District announced the change before a Dupont Circle neighborhood group Monday.

Police officials have wrestled with the growing problem of panhandling. Neighborhood groups and business leaders frequently complain of aggressive beggars, and police in the past have had little clout to move them on.

Earlier this year, Police Chief Isaac Fulwood Jr. tried to address the problem by getting officers to enforce laws that deal with disorderly conduct and indecent language.

Later, the city's corporation counsel decided, based on what was interpreted as a favorable court ruling, that the D.C. ordinance would withstand a challenge on constitutional grounds.

The ruling, by the 2nd U.S. Court of Appeals, overturned a lower court ruling that said begging in New York City subways was protected by the First Amendment.

Most of the District's vagrancy law, which contains the ordinance now being used, was declared unconstitutional by a federal appeals court. But the ordinance itself was never challenged and has remained on the books.