WASHINGTON — Multiple congressional computers have been hacked by people working from inside China, lawmakers said today, suggesting the Chinese were seeking lists of dissidents.

Two congressmen, both longtime critics of Beijing’s record on human rights, said the compromised computers contained information about political dissidents from around the world. One of the lawmakers said he’d been discouraged from disclosing the computer attacks by other American officials.

Rep. Frank Wolf, a Republican of Virginia, said four of his computers were compromised, beginning in 2006. Rep. Chris Smith of New Jersey, a senior Republican on the House Foreign Affairs Committee, said two of his computers were attacked, in December 2006 and March 2007.

Mr. Wolf said that following one of the attacks, a car with license plates belonging to Chinese officials went to the home of a dissident at Fairfax County, Va., outside Washington and photographed it.

During the same time period, The House International Relations Committee — now known as the House Foreign Affairs Committee — was targeted at least once by someone working inside China, a committee spokeswoman, Lynne Weil, said.

Today’s disclosures came as American authorities continued to investigate whether Chinese officials secretly copied the contents of a government laptop computer during a visit to China by the Commerce Secretary, Carlos M. Gutierrez, and used the information to try to hack into Commerce Department computers.

The Pentagon last month acknowledged at a closed House Intelligence committee meeting that its vast computer network is scanned or attacked by outsiders more than 300 million times each day.

Mr. Wolf said the FBI had told him that computers of other House members and at least one House committee had been accessed by sources working from inside China. The Virginia Republican suggested that Senate computers could have been attacked as well.

He said the hacking of computers in his Capitol Hill office began in August 2006, that he had known about it for a long time and that he had been discouraged from disclosing it by people in the U.S. government he refused to identify.

“The problem has been that no one wants to talk about this issue,” he said. “Every time I’ve started to do something I’ve been told ‘You can’t do this.’ A lot of people have made it very, very difficult.”

The FBI and the White House declined to comment.

The Bush administration has been increasingly reluctant publicly to discuss or acknowledge cyber attacks, especially ones traced to China.

In the Senate, the office of Senator Durbin, a Democrat of Illinois, who chairs the Senate’s subcommittee on humanitarian issues, asked the sergeant at arms to investigate whether Senate computers have been compromised.

Mr. Wolf said the first computer hacked in his office belonged to the staffer who works on human rights cases and that others included the machines of Mr. Wolf’s chief of staff and legislative director.

“They knew which ones to get,” Dan Scandling, who currently is on leave of absence from his job as Mr. Wolf’s chief of staff, said. “It was a very sophisticated operation,” he said. “The FBI verified that it had been done.”

Mr. Smith said the attacks on his office computers were “very much an orchestrated effort.”

He said that after the first intrusion in December 2006, “that was the last time” his office put the names of dissidents on its computers.

In Beijing, the Chinese Ministry of Foreign Affairs had no immediate comment on the allegations by Messrs. Wolf and Smith.

Last week, China denied the accusations regarding Mr. Gutierrez’s laptop and the alleged effort to hack Commerce Department computers.

Mr. Wolf said he was introducing a House resolution that would help ensure protection for all House computers and information systems.

It calls for the chief administrative officer and sergeant at arms of the House, in consultation with the FBI, to alert members and their staffs to the danger of electronic attacks. Wolf also wants lawmakers to be fully briefed on ways to safeguard official records from electronic security breaches.

“My own suspicion is I was targeted by China because of my long history of speaking out about China’s abysmal human rights record,” Wolf said in a draft of remarks he prepared to give on the House floor.

He said Congress should hold hearings, specifically the House Intelligence Committee, Armed Services Committee and Government Operations Committee.

Speaking generally in May 2006, Mr. Wolf called Chinese spying efforts “frightening” and said it was no secret that America is a principal target of Chinese intelligence services.

Mr. Wolf thinks that President Bush should stay away from the Olympics because of China’s human rights record.

He also has been outspoken on the subject of violence in the Darfur region of Sudan, where China has major oil interests.

Mr. Smith has introduced the Global Online Freedom Act which would prohibit American internet companies from cooperating with countries such as China that restrict information about human rights and democracy on the Internet.

Messrs. Wolf and Smith both traveled to Beijing 17 years ago seeking the release of 77 people imprisoned or under house arrest because of their religious activities.