Tom Downey, a former congressman who has been helping the vice president prepare for debates against Bush, turned the material over to his lawyer. The attorney gave the package to the FBI to determine whether the documents and tape were "illegally obtained from the Bush campaign," said Gore spokesman Mark Fabiani.

"Clearly, this is something that should not have been sent to me," Downey said in a statement. "I have directed that all of the materials be turned over to law enforcement officials where they can deal with them appropriately."

Fabiani said Gore's staff did not know whether the package was a hoax or actual Bush campaign material. It came with a postmark from Austin, Texas, home of Bush's headquarters. The return address included a sender's name but Downey did not recognize it, his attorney said.

"Using these materials was never an option," said Downey, who was set to play Bush in Gore's debate preparations. "To do so would dishonor a great American tradition of open and honest debates."

Gore chairman William Daley called Bush chairman Don Evans to notify him about the package.

Bush spokesman Ari Fleischer said: "We do not know what the Gore campaign claims to have in their possession and we would like to review the material. Our attorneys have asked to review it."

Bush communications director Karen Hughes said the campaign is not conducting an internal investigation because people who had "legitimate access" to the tapes were very few. "So obviously we don't feel that ... they came from our staff," Hughes said.

Asked whether they were satisfied with the way the Gore campaign was handling the situation, Hughes said: "I think it was right for them to turn them over to the authorities."

Bush campaign attorneys have asked the FBI for access to the materials to view them and determine if they are authentic, but nothing had been set up.

Downey's attorney Marc Miller said he rejected a request by Bush lawyer Ben Ginsberg to review the materials. "The FBI is in a better position to determine what should be done about this," Miller said.

FBI spokesman Bill Carter said, "The preliminary information provided to the FBI is being assessed to determine which, if any, federal statutes are applicable."

The development came on the eve of a meeting between officials with the Gore and Bush campaigns that could result in a schedule of fall debates. The meeting is set to be held at the offices of the Commission on Presidential Debates in Washington.

Fabiani disclosed the development to The Associated Press.

The package arrived by mail at Downey's office in Washington at 10:28 a.m. EDT Wednesday. He opened the package, which contained a videotape and documents that appeared to relate to the Bush campaign.

Downey notified Miller, who took the documents about 11:15 a.m. and called the FBI. Miller later said two FBI agents picked up the package from his office. Fabiani said Downey has decided to stop participating in debate preparations.

Downey has not disclosed to campaign officials what is in the package, Fabiani said. Miller also refused to detail the contents in an interview with the AP.

A senior Bush adviser, speaking on condition of anonymity, said the campaign does have videotapes of Gore's past debates, Bush's past debates and Bush's debate preparation sessions.

There are also internal documents that detail potential strategies against Gore, said the official, who added that it was inconceivable that the information was leaked to a Gore partisan.

The situation was somewhat reminiscent of a case in which debate documents from President Carter's 1980 re-election campaign turned up later in the files of Republican challenger Ronald Reagan. That was never fully explained, despite an FBI investigation.