Chinese American groups, breaking months of public silence, have expressed concern to federal officials that espionage suspect Wen Ho Lee may have been targeted on the basis of his ethnicity and that his case could trigger what one group called "a virulent anti-Chinese frenzy in this country."

"Such a high-profile prosecution, with its attendant media circus atmosphere, could do incalculable harm to the welfare of millions of law-abiding Chinese and to our foreign policy toward China itself," the Committee of 100, a New York-based group of prominent Chinese Americans, said this week in a letter to Attorney General Janet Reno and Energy Secretary Bill Richardson.

The committee's letter came less than a week after the Senate Governmental Affairs Committee sharply criticized investigators at the FBI and the Department of Energy for failing to pursue other possible suspects, since there is no direct evidence that either Lee or anyone else at Los Alamos National Laboratory gave nuclear secrets to China.

The President's Foreign Intelligence Advisory Board voiced the same criticism in June, finding that investigators focused virtually all of their energies on Lee "despite the potential that the source or sources of these disclosures were other than the bomb designers at the national weapons labs."

Lee, a Taiwan-born nuclear physicist and U.S. citizen, was fired in March from his job in a top-secret division at Los Alamos for alleged violations of security regulations. Lee had been designated three years earlier as the prime suspect in an investigation of China's alleged theft of design data on the W-88, America's most advanced nuclear warhead.

While senior U.S. officials acknowledge that they lack evidence to bring espionage charges against Lee, they are considering whether to charge him with a crime for transferring classified information from the secure computer system at Los Alamos to his vulnerable desktop computer.

Lee has denied passing classified information to China. In an interview on the CBS television program "60 Minutes" earlier this month, he described the transfer of classified data as "a very common practice," adding: "I don't understand why I was singled out for this particular issue."

Lee went on to say that he believed investigators targeted him because he was the only "Oriental or Chinese [person] working on the top secret [weapons program] for the last 18 years."

Less than a week after the broadcast, another Asian American rights group, the National Asian Pacific American Legal Consortium, took Richardson to task for remarking to the press that Lee had "unfairly tried to use the race card" in his "60 Minutes" appearance.

"Given the evidence that is publicly available to date, there is reason to believe that ethnic targeting is taking place," Karen K. Narasaki, the consortium's executive director, said in a letter to the energy secretary. "Rather than further contributing to the so-far unsubstantiated speculation that Mr. Lee has engaged in spy activities as you did when you recently declared that he would never work at another lab, we would hope you would take the concerns more seriously."

A third group, the Washington-based Organization of Chinese Americans, also has expressed its concerns to Richardson, according to its executive director, Daphne Kwok.

"We are constantly having to prove our loyalty, whether it's with campaign finance or this issue," Kwok said. "Chinese American scientists, not only in these national labs, but scientists working for military contractors and in the defense industry, are very fearful for their own livelihood--they're fearful that they're under suspicion as being Chinese spies."

Wei Kao, chairman of the Chinese American Engineers and Scientists Association of Southern California, said Washington's obsession with Chinese espionage already has prompted many members of his organization to forgo travel to international technical conferences in China.

If the Justice Department prosecutes Lee for transferring classified weapons data to his unclassified computer, regardless of the outcome, Kao said, "it's going to give people a lot of excuses to stereotype Chinese Americans. It's happening already, absolutely."

The media attention to such a trial, he added, could affect the careers of thousands of Chinese American scientists and make it more difficult for them to obtain security clearances.

Richardson refused to retract his criticism of Lee's televised remarks but issued a lengthy statement yesterday saying he understands the concern of the Chinese American organizations.

"As a Hispanic American, I have an understanding about racism," he said. "I will not tolerate it at the Department of Energy or any of our labs and facilities. I've issued a directive to the department's managers and laboratory directors that I will not stand for racial profiling or discrimination of any kind."

He said he fired Lee "because the employee committed serious breaches of security rules. But the actions of any individual should not, and do not, and will not reflect on any other citizen."

Richardson issued the statement one day after announcing that he was recommending disciplinary action against two former counterintelligence officials at Los Alamos and the lab's former director for failing to respond quickly and effectively to the espionage allegations.