New federal rules that require charities and nonprofits to screen all their employees and others for any connections to terrorist organizations are roiling the charitable world, and yesterday 16 national nonprofit groups vowed to fight the regulations.

A coalition of nonprofits -- including the American Civil Liberties Union, the Sierra Club and Amnesty International USA -- announced an effort to try to force the agency that administers the multimillion-dollar giving campaign among federal workers to rescind the requirement.

"We believe that this policy is both misguided and dangerous," said Anthony Romero, executive director of the ACLU, which last year received about $500,000 from the Combined Federal Campaign.

In protest, the ACLU has quit the campaign, and officials said yesterday that a suit is planned against the CFC, alleging that the rule violates ACLU employee privacy rights.

Two other coalition members, Amnesty International USA and the Electronic Frontier Foundation, said yesterday that they have also dropped out of the CFC because of the requirement.

"We are certainly against terrorism," said Chip Pitts, board chairman of Amnesty International USA, which received about $350,000 from federal employees through last fall's CFC campaign. "The problem with these lists is that they are notoriously riddled with errors [and] they are subjective."

The focus of the uproar is a relatively obscure rule change by the Office of Personnel Management, which oversees the CFC. It requires the more than 2,000 charities applying to participate in the CFC, which raised $248.3 million from federal workers and military personnel last year, to certify they do not "knowingly employ" suspected terrorists.

The certification requires charities to consult lists maintained by the federal government. But, the charities say, the lists are voluminous and confusing -- containing tens of thousands of names, many of which sound similar to or are common Muslim and other ethnic names.

The OPM has declined repeated requests to comment on the issue, citing threatened litigation by the ACLU.

But in a letter sent Monday to the ACLU, the OPM defended its action. The letter, signed by Mara T. Patermaster, director of CFC operations at OPM, said the agency is required to impose the screening under an executive order signed by President Bush shortly after the Sept. 11, 2001, attacks. The order prohibited Americans from having financial ties with suspected terrorists or terrorist organizations.

"OPM feels a responsibility to ensure that it does not facilitate, through the CFC, the transfer of funds donated by Federal employees through or to the hands of persons designated for their ties to terrorists or terrorist supporters," the letter said.

The OPM directive is the latest in a number of efforts by government agencies and private philanthropic groups to ensure that neither public nor private dollars make their way to terrorist organizations.

The role of charities in funding terrorists has become the focus of increasing concern. Late last month, the Justice Department announced the indictment of the nation's largest Muslim charity, the Holy Land Foundation for Relief and Development, and seven of its top officials on charges that they funneled millions of dollars to groups associated with Hamas, a Palestinian group that the U.S. government considers a terrorist organization.

In recent months, many government agencies and private philanthropic organizations have begun requiring the nonprofit groups they fund to verify that they do not support terrorist organizations.

Earlier this year, the $2 billion Charles Stewart Mott Foundation began requiring the organizations it funds to certify that they do not engage in "terrorist activity." And the $10 billion Ford Foundation daily checks the names of its 4,000 grantees against the government lists.

Ford spokesman Alex Wilde said the group is legally bound under the USA Patriot Act to check whether its grantees are on the government lists of terrorists. "Beyond that," he added, "it's just the right thing to do."

Some of the provisions are drawing protests from a variety of charity officials, who say they are increasingly concerned that the government's zeal to stamp out terrorist-supported charities is hurting legitimate groups.

A half-dozen nonprofit organizations that receive millions of dollars in grants from the U.S. Agency for International Development have asked the agency to revise its detailed requirements.

USAID requires each aid group to certify "it has not provided and does not knowingly provide material support" to groups that appear on lists of suspected terrorists.

Aid groups that work with thousands of small overseas nonprofit organizations say the provision is overly broad and unrealistic.

The requirement is "just legally a bit over the top," said Michael Wiest, chief of staff of Catholic Relief Services, which last year received about $350 million from USAID. The group works with about 50,000 agencies abroad each year.

Wiest emphasized that his organization supports the U.S. war on terror but said that the USAID requirement is "asking you to certify things that no one could conceivably ever know."

However, Jim Kunder, USAID's assistant administrator for Asia and the Near East, who has been negotiating with aid groups to revise the requirement, said that under the USA Patriot Act, USAID must make such demands.