Federal agents served search warrants Friday at two U.S.-based Islamic charities that have come under close scrutiny of federal investigators trying to identify groups providing support to terrorists.

FBI spokeswoman Ebony Harrel would not say what, if anything, agents seized from the two organizations, Global Relief Foundation in Bridgeview and the Benevolence International Foundation in Palos Hills. The search warrants were sealed.

At Global Relief's headquarters, agents took records as well as furniture, said Asim Ghafoor, a foundation spokesman. The organization issued a statement denying any link to terrorist activities.

"We are in the business of helping innocent civilians and take every precaution to ensure our aid does not go to support or subsidize any nefarious activity," the group said.

A messages left at the Benevolence International Foundation was not immediately returned.

The search warrants were served the same day that NATO-led peacekeepers and United Nations police raided two Global Relief offices in Yugoslavia.

The Global Relief Foundation "is suspected of supporting worldwide terrorist activities and is allegedly involved in planning attacks against targets in the USA and Europe," the NATO statement said.

Global Relief raises about $5 million a year for programs in mainly Muslim countries around the world. It did not appear on the U.S. Treasury Department's list of organizations and individuals whose assets are being frozen because of their alleged ties to terrorism.