LOS ANGELES – The early morning light reveals a no loitering sign and a half-dozen people sleeping beneath it in tents on the Skid Row sidewalk.

A few bony men scatter as a police cruiser rolls up. But Glenda Caldwell isn’t stirring from beneath her filthy blankets, sprawled beside a shopping cart filled with crumpled cans and paper.

“Where do you want me to pack up and go? To hell?” Caldwell bellows at the two officers and their sergeant.

Starting this month, a beefed-up police force is arresting people who violate a daytime sidewalk sleeping ban. Plenty worse happens in a neighborhood that for decades has been virtually surrendered to crime, grime and vagrancy but now sits on the fringe of an attempted downtown revival.

Critics deride the sidewalk sleeping ban as overzealous, but police Chief William Bratton insists it’s a way to salvation for Skid Row. It’s the same kind of bust-small-crimes approach he used to control crime in New York City more than a decade ago.

Enforcing the sidewalk-sleeping ordinance is a stark change for a neighborhood where police traditionally have tried to contain crime from spreading, not stop it. The ordinance is considered one of the most restrictive in the nation and has drawn fire from homeless advocates and their allies.

“L.A. remains the only city in the U.S. whose answer to homelessness is to criminalize being poor,” said Mark Rosenbaum, a lawyer with the American Civil Liberties Union, which has sued to stop the city from enforcing the ordinance. “A program that relies on criminalization isn’t going to solve any of the social problems.”

More than 200 of the nation’s 250 largest cities have ordinances prohibiting sidewalk sleeping, sitting and loitering, according to a study by the National Coalition for the Homeless. How much these ordinances are enforced can vary day to day, and the group’s acting executive director, Michael Stoops, said he’d never heard of another city enforcing a no camping ordinance during the day, but not at night.

With 50 new foot patrol officers redeployed to Skid Row, Bratton’s Safer City Initiative attempts to improve an area he calls the worst open-air drug market in the country. By enforcing minor crimes, police will erode a long-accepted feeling of lawlessness, he said. Police arrested about 600 people for drug selling in the first week of the initiative.

“We’re not here to cure homelessness,” said Police Capt. Andrew Smith, who is based in Skid Row. “We’re here to … end what some call a Mardi Gras of crack here, where it’s almost a free zone of dope and prostitution and aggravated assaults.”