On a recent evening in downtown D.C., dozens of black youths gathered at their usual meeting spot on the steps of the National Portrait Gallery. Suddenly, according to witnesses, a girl in the crowd snatched some hair extensions from the head of another girl and a chase ensued.

“I walked past and all of a sudden the crowd started cheering and when I looked back, the girl who had taken the hair was punching the other girl to the ground,” Bob Daly, owner of California Tortilla near the Gallery Place Metro stop, told me. “Then five other girls joined in and started kicking her.”

The fight was the last straw for Daly who, along with several other business owners, met with D.C. police last week to complain that rowdy youths are driving away customers and hindering the revitalization of downtown.

They want police to take preemptive action by cracking down on even minor offenses, such as “disturbing the peace.” To hear the youngsters tell it, however, the police have been cracking down on them all along.

But the youngsters call it harassment, and they complain that the law-abiding majority of black youths are being treated like suspects because of a misbehaving few.

“My friends and I got locked up two months ago for walking across the sidewalk,” Ke’Shayla Thorne, 17, a student at Spingarn High School in Northeast, told me. “The police said, ‘Come here, you’re under arrest.’ But other people walk like that all the time and they expect black kids to move off the sidewalk and let them pass. Nobody locks them up.”

The charges against the girls — disorderly conduct — were dismissed in D.C. Superior Court a few days later.

I recently met with Thorne and several of her friends at a restaurant near Seventh and H Street NW, a block from the Portrait Gallery where they congregate on weekends. In their view, a war is being waged to exclude groups of black youngsters from public spaces throughout the Washington area — with proposals for curfews in Montgomery County, shuttered go-go clubs in the District and Prince George’s County and intense surveillance by store security guards in Georgetown and downtown D.C.

After a brawl near the Gallery Place Metro stop last summer, business owners had a high-pitch noise device installed at the stop aimed at irritating youthful ears. The device was removed amid protests that it constituted a form of age discrimination.

But business owners say a serious problem persists. Some of their stores have been “bum rushed” by large groups of shoplifters. Youths routinely hang out in their doorways, using foul language.

“It’s menacing,” Daly said. “I know people who no longer come down here on Fridays or Saturdays. It’s ridiculous. Why do they have to suffer because of such obnoxious behavior?”

That’s exactly what many of the law-abiding black teenagers and young adults want to know.

“It’s so unfair,” said Lakiesha Bennett, 20, who lives in the Trinidad neighborhood in Northeast. “The police follow us onto the subway and watch us until we get off. Some stores won’t let but a few us in at one time. They have dress codes that just happen to ban the style of clothes many of us wear. It’s like, we can’t go anywhere or do anything.”

First District Police Cmdr. Daniel P. Hickson, whose service area includes downtown, expressed sympathy for both the youngsters and the business owners.

“I want these businesses to succeed, but a lot of things that are a great annoyance don’t always rise to the level of being criminal,” he said. For instance, there is no law against “loitering” in the District. “We’re just trying to keep peace in the middle,” he said.

Daly, for his part, is certainly not against having young people visit downtown. He just wants them to behave — and not just for the sake of his business, but for theirs, too.

Turns out, he was one of only two people who dared to step in and break up the fight between the girls — only to learn that the one he’d help to rescue refused to press charges.

“Even she was afraid of them,” Daly said.

As Thorne and her friends see it, that’s still no reason for anyone to be afraid of them.