The Quantico Town Council passed a curfew Thursday prohibiting minors from being outside between 10 p.m. and 6 a.m., unless they are on a legitimate errand.

The ordinance prohibits children under 18 from "loitering, idling, standing around, playing or wandering on foot whether or not on private property" in the town of 600, which is 35 miles from Washington. It carries a maximum penalty of 30 days in jail or a $300 fine.

Adolescents are permitted on the street if they are going to or from an activity, or on a legitimate errand. Police will warn youths that they must go home, and if they fail to comply, they may be arrested, said Quantico Police Chief Leo Rodriguez.

A rash of vandalism that began several months ago prompted the curfew ordinance, Rodriguez said, adding, "We always found kids in that age group in the vicinity."

Town residents were especially concerned about small groups of 13-, 14- and 15-year-old girls who were outside with older teens and adults after midnight. "There was no way to actually control that. If people are moving, they aren't loitering," Rodriguez said.

More than 40 Virginia localities have some sort of curfew for minors, but most are not enforced, said Kent Willis, executive director of the Virginia chapter of the American Civil Liberties Union. The ACLU opposes most curfews because they are overly broad and are often enforced selectively.

Curfews are "typically shortcut attempts to solve problems that have deeper roots," Willis said.

A federal judge declared unconstitutional a curfew law passed last year in the District.