The FBI searched offices of a prominent public relations firm Tuesday, looking for information about its client Saudi Arabia, law enforcement sources said.

The firm, Qorvis Communications LLC, which was founded in 2000, bills itself as providing "communications for Wall Street, Main Street and K Street." Qorvis has offices in the District and Tysons Corner, and its clients also include Time Warner Inc. and the Urban League.

The FBI searched three of the firm's offices Tuesday afternoon, sources said. Agents delivered subpoenas at a fourth Qorvis office.

Michael Mason, head of the FBI's Washington field office, declined yesterday to characterize the nature of the investigation or identify the places that were searched. "We did execute searches at three locations," he said.

Officials at the U.S. attorney's office in Washington said the case is under seal and would not reveal details.

"The raids are in conjunction with an ongoing investigation and therefore it would be inappropriate for me to comment," said Channing Phillips, spokesman for the U.S. attorney's office in Washington.

Qorvis said the company understood that the government is conducting a "compliance inquiry" under the Foreign Agents Registration Act. Under that law, the government keeps track of the lobbying activities of foreign governments and their representatives. The rigorous registration and reporting system is overseen by the Justice Department.

Saudi Arabia is the only foreign government on Qorvis's client list.

"Qorvis has fully complied with this registration statute and we feel confident this will be resolved favorably," the company said.

Violations of the law have been prosecuted only a handful of times since it was passed in 1938. But at least two recent cases have been filed involving Iraq.

In January, Khaled Abdel-Latif Dumeisi, former publisher of an Arabic newspaper in suburban Chicago, was convicted of failing to register as a foreign agent for Saddam Hussein's regime in Iraq. Dumeisi was sentenced in March to 46 months in prison on those and other charges.

Susan P. Lindauer, a Takoma Park antiwar activist, has been charged under the law and accused of accepting cash from Iraqi intelligence agents. She has denied wrongdoing.

A Justice Department report on the law provided a window into the company's activities. It stated that the Saudi Arabian Embassy paid Qorvis $14.6 million for a six-month period, ending Dec. 31, 2002, for lobbying and public relations, including the distribution of material "to promote public awareness" of Saudi Arabia's "commitment in the war against terrorism and to peace in the Middle East," the report said.

On behalf of Saudi Arabia, Qorvis also contacted the media, congressional staff members and Bush administration officials to discuss Middle East issues, child abduction and a communications strategy for the crown prince's visit with President Bush, the document said.

Staff writer Allan Lengel contributed to this report.