Federal agents yesterday raided 14 sites across Northern Virginia, many with links to the Middle East, seizing boxes of documents in an ongoing investigation of the funding of terrorist groups. No arrests were made, and none of the businesses was closed down.

Government sources said the investigation is looking at charities and other organizations that may have contributed money to international groups that sponsor terrorist activities.

Federal officials said the search warrants in Virginia and one in Georgia were issued as part of Operation Green Quest, being conducted by a counterterrorism financial task force created by the Treasury Department in October. Affidavits giving the reasons for the searches were sealed and were not provided to those who were searched.

Agents from the U.S. Customs Service, which heads Operation Green Quest, and officers from nine other federal agencies and from police departments swooped into locations in Herndon, Falls Church and Leesburg and other sites in Fairfax County about 10:30 a.m. Federal and local officials would not disclose exact locations for any of the searches.

But Customs agents were busy loading up boxes throughout the afternoon at two offices in Herndon: at the International Institute for Islamic Thought and at MarJac Investments, both on Grove Street. Shortly before 4 p.m., the investigators drove a large U-Haul truck into a parking lot near both. Ahmed Totonji, a vice president at the institute, said he was surprised by the federal interest in his firm, a nonprofit Islamic think tank that has been in Herndon since 1981. He said no one had told him why it was being searched.

"We have no knowledge of this kind of thing going on," Totonji said, "and we will cooperate 100 percent."

The institute has branches in 12 countries in addition to its Herndon headquarters and describes itself as "an intellectual forum working from an Islamic perspective to promote and support research projects, organize intellectual and cultural meetings and publish scholarly works."

But the institute also has been linked to controversial groups in the Middle East. It has made large financial contributions to the World Islamic Studies Enterprise in Tampa. In November, the Justice Department called the Tampa group a "front organization that raised funds for militant Islamic-Palestinian groups such as the Palestinian Islamic Jihad (PIJ) and Hamas. The PIJ, designated by the Secretary of State as a terrorist organization, has claimed responsibility for several acts of terrorism."

Until the mid-1990s. the World Islamic Studies Enterprise was an academic institute affiliated with the University of South Florida. Federal agents searched its office in 1995 and eventually froze its assets.

Tax records show that the Herndon institute made contributions to the group until at least 1994.

Steven Emerson, a journalist and author of the bestselling "American Jihad," said yesterday's raids were part of a money-laundering investigation launched by the federal government since the Sept. 11 terrorist attacks.

"It is part of the ongoing problem of nonprofit humanitarian groups commingling their funds with support for terrorist groups," he said.

Federal agents yesterday also raided the Graduate School of Islamic and Social Sciences on Miller Drive in Leesburg. Taha Al-alwani, president of the school, said authorities arrived at 10:30 a.m., confined employees to the lobby and began searching computers and financial records. They said little except that they were there to examine the school's finances.

Each employee was interviewed separately about his job, and when staff members asked to use the restroom, they were escorted by armed agents. The school, which opened in 1996, was the first in the country approved by the Pentagon to train Muslim chaplains. Nine of the military's 13 Muslim chaplains have studied there.

"I'm very upset, because after all our loyalty and service to our country, here we see ourselves in this position," Al-alwani said.

Agents also seized documents at MarJac Investments Inc., in Herndon, a consulting firm that has offices in Egypt, Turkey, Malaysia, Canada and Chile.

Operation Green Quest was created to identify and shut down the sources of terrorist funding by using the Treasury Department to freeze accounts, seize assets and prosecute those assisting terrorists.