He was scared and injured - bruised and swollen for several days - but hardly surprised.

At his school, Lafayette High in Brooklyn, Chinese immigrant students like him are harassed and bullied so routinely that school officials in June agreed to a Department of Justice consent decree to curb alleged "severe and pervasive harassment directed at Asian-American students by their classmates." Since then, the Justice Department credits Lafayette officials with addressing the problem - but the case is far from isolated.

Nationwide, Asian students say they're often beaten, threatened and called ethnic slurs by other young people, and school safety data suggest that the problem may be worsening. Youth advocates say these Asian teens, stereotyped as high-achieving students who rarely fight back, have for years borne the brunt of ethnic tension as Asian communities expand and neighborhoods become more racially diverse.

"We suspect that in areas that have rapidly growing populations of Asian-Americans, there often times is a sort of culture clashing," said Aimee Baldillo of the National Asian Pacific American Legal Consortium. Youth harassment is "something we see everywhere in different pockets of the U.S. where there's a large influx of (Asian) people."

In the last five years, Census data show, Asians - mostly Chinese - have grown from 5 percent to nearly 10 percent of Brooklyn residents. In the Bensonhurst neighborhood, historically home to Italian and Jewish families, more than 20 percent of residents now are Asian. Those changes have escalated ethnic tension on campuses such as Lafayette High, according to Khin Mai Aung, staff attorney at the Asian-American Legal Defense and Education Fund, which is advocating for Lafayette students.

"The schools are the one place where everyone is forced to come together," Aung said.

Brooklyn's changes mirror Asian growth nationally. Between 1980 and 2000, the number of Asians and Pacific Islanders grew from 3.7 million to nearly 12 million. After Latinos, Asians are the nation's fastest-growing ethnic group.

Stories of Asian youth being bullied and worse are common. In recent years:

?A Chinese middle schooler in San Francisco was mercilessly taunted until his teacher hid him in her classroom at lunchtime.

?Three Korean-American students were beaten so badly near their Queens high school that they skipped school for weeks and begged to be transferred.

?A 16-year-old from Vietnam was killed last year in a massive brawl in Boston.

Some lawmakers have responded. The New York City Council, after hearing hours of testimony from Asian youth, last year passed a bill to track bullying and train educators on prevention. Also last year, California Assemblywoman Judy Chu won passage of a new law to allow hate crimes victims more time - up to three years - to file civil suits; the bill was inspired by a 2003 San Francisco incident in which five Asian teens were attacked by a mob of youth.

In August, the Oakland-based Asian Pacific Islander Youth Violence Prevention Center organized a first-ever conference on the subject in Sacramento. Isami Arifuku, assistant director of the center, said she expected about 200 participants but nearly double that number attended.

Experts offer several broad explanations for the bullying problem.

In the broadest strokes, Baldillo said, Asian youth are sometimes small in stature and often adhere to cultural mores urging them to avoid confrontation and focus on academics. Many don't report bullying because they fear repercussions or don't want to embarrass their families, she added.

Language barriers also exacerbate the situation. "I have to hear, '(Expletive) Chinese!' at least three times a day, and they always say it to people who look weaker and don't speak English," said Rita Zeng, 19 and a senior at Lafayette High. The parents of limited-English students often have little access to translators and struggle to advocate for their children, Aung said.

Chen Tsu described his beating in April at a subway station, saying through a translator: "Those guys looked like they could kill somebody. ... I was scared to go back to school."

Increasingly, some victims are fighting back. A 2003 California survey by the Services and Advocacy for Asian Youth Consortium found that 14 percent of Asian youth said they join gangs for protection. Department of Justice school crime data found the number of Asian youth carrying weapons nearly tripled from 1999 to 2001.

"There are more Asian kids being brought to juvenile court for assault and battery," Arifuku said. "The thing we're finding in their history is that they had been picked on - called names and teased - and in some cases they lashed out and retaliated."

Advocates and students say that, typically, large fights erupt after weeks or months of verbal taunting.

That's what happened at Edison High School in Fresno, Calif., according to Malcolm Yeung of the Asian Law Caucus in San Francisco. For months starting late last year, Hmong students had been repeatedly called names and had food thrown at them.

"There had been patterns of this happening over and over again," said Yeung, whose group investigated the case on behalf of Asian students. "But the school had overlooked the issue."

On Feb. 25, the lunchtime taunting escalated into fights involving at least 30 students, according to Susan Bedi, spokesman for Fresno Unified School District. Seven students were treated for injuries, 12 were suspended and two faced expulsion, she said. Eight were convicted of misdemeanor assault, said Fresno police Sgt. Anthony Martinez.

This year, officials at Edison High added more security and started an on-campus human relations council to address ethnic tension, Bedi said.

At Lafayette High, tension has long been high on campus and in surrounding areas, said Steve Chung, president of the United Chinese Association of Brooklyn, whose group was founded in late 2002 after an earlier student beating. That incident "was like the ignition - it started a fire" in the community.

The student, a straight-A senior, was thrashed to unconsciousness while anti-Chinese slurs were yelled at him. Some news reported dubbed the school "Horror High," and Chinese students began going public about the problem.

"The more we dug into Lafayette High School, the more we found," Chung said.

Aung's probing revealed that school administrators seemed reluctant to intervene, translation services for parents and students was spotty and teachers who reported the problems may have been punished.

School officials say some reports were exaggerated. But "the problems there went back many, many years," said Michael Best, general counsel for New York City schools. Since signing the consent decree in June, he said, "the situation at the school in our view is very, very different." A Justice Department spokesman agreed that the school has been "very responsive."

Teachers this year are getting training to curb harassment, translation services throughout the district have been beefed up, and race relations experts are working with students and staff on campus, deputy New York schools chancellor Carmen Farina said.

Last year, Lafayette's longtime principal retired, and many are optimistic about the new principal, Jolanta Rohloff. In addition, new vice principal Iris Chiu is fluent in Chinese and working closely with parents and students. "We actively sought someone that we knew could handle the delicacy of the school," Farina said.

Still, she said, an incident already has been reported since school started: An Asian student was attacked by several classmates on his way to the subway. He suffered minor injuries.