WASHINGTON — A Defense Department analyst and a former engineer for Boeing Co. were charged yesterday in separate spy cases for allegedly handing over military secrets to the Chinese government, the Justice Department said.

Additionally, two immigrants from China and Taiwan accused of working with the defense analyst were arrested after an FBI raid yesterday morning on a New Orleans home where one of them lived.

The two cases — based in Alexandria, Va., and Los Angeles — have no connection, and investigators said it was merely a coincidence that charges would be brought against both on the same day.

The arrests mark China’s latest attempts to gain top-secret information about American military systems and sales, Assistant Attorney General Kenneth Wainstein said. He described China as “particularly adept, and particularly determined and methodical in their espionage efforts.”

An official at the Chinese Embassy did not immediately respond to a request for comment. In the first case, prosecutors said weapons systems policy analyst Gregg Bergersen, 51, of Alexandria, Va., sold classified defense information to a New Orleans furniture salesman. In return, the salesman, a Taiwan native identified as Tai Kuo, a 58-year-old naturalized American citizen, forwarded the information to the Chinese government.

The data outlined every planned American sale of weapons or other military technology to Taiwan for the next five years, prosecutors said.

It’s not clear how much money Mr. Bergersen received for the classified information, or if he was even aware it was intended for the Chinese government.

A third alleged conspirator in the case, Chinese national Yu Xin Kang, 33, served as the go-between for Mr. Kuo and the People’s Republic of China, prosecutors say.

Messrs. Kuo and Bergersen, who worked at the Defense Security Cooperation Agency in Arlington, Va., were arraigned before Magistrate Judge John Anderson at the federal courthouse in Alexandria. Mr. Bergersen was charged with conspiracy to deliver national defense information to a person not entitled to receive it. He faces a maximum of 10 years in prison.

Tai Kuo was charged with conspiracy to deliver national defense information to a foreign government. He faces life in prison if convicted. Mr. Kang, 33, who faces the same charges as Mr. Kuo, appeared briefly in federal court in New Orleans. But U.S. Magistrate Judge Louis Moore Jr. postponed the hearing until an interpreter could be brought in when it appeared Mr. Kang, who cried throughout, did not understand the charges being read.

In the second, unrelated case, a former Boeing engineer, Dongfan “Greg” Chung, 72, was arrested on charges of working as an unregistered agent for the Chinese government who stole trade secrets from the defense contractor. The stolen data largely focused on aerospace programs, including the Space Shuttle, prosecutors said.

Mr. Chung, a naturalized American citizen, was indicted last week on espionage, conspiracy, and obstructing justice charges that were unsealed yesterday.

Over an 18-year span, Mr. Chung traveled to China many times to deliver lectures on the Space Shuttle and other programs, and he allegedly met with Chinese government officials there to discuss how to transfer American data.

Mr. Chung, who has a security clearance, worked for contractor Rockwell International between 1973 and 1996, when Boeing acquired Rockwell’s defense and space firm. He retired from Boeing in 2002 but returned the next year as a contractor. He ultimately left Boeing in 2006.