In an unusual bipartisan step, Republican and Democratic leaders in the U.S. House of Representatives are calling for the U.S. Justice Department to return documents seized by federal agents in an unprecedented search of a lawmaker facing a bribery investigation.

It is the latest development in the still unfolding story surrounding Democratic Congressman William Jefferson, whose Capitol Hill office was searched for 18 hours as part of a federal investigation into his activities underway since last year.

Members of Congress from both sides of the political aisle have been outraged by the FBI search of Jefferson's congressional office, calling it a breach of the principle of separation of powers and a violation of the Constitution.

The powerful Republican Speaker of the House, Dennis Hastert, raised the matter in meetings with President Bush this week and on Wednesday called for the Department of Justice to return documents taken:

"We want to protect the prerogatives of the House as far as the Constitution [is concerned]," said Dennis Hastert. "We think those materials ought to be returned. We also think that those people involved in that issue ought to be frozen out of that [the investigation] just for the sake of the constitutional aspect of it."

A Democrat from the southern Gulf coast state of Louisiana, Congressman Jefferson was videotaped last year by the FBI taking $100,000 supplied by a federal informant from the trunk of a car.

Federal authorities say $90,000 of that money was later found in a freezer in Jefferson's home, wrapped in food containers and aluminum foil.

Jefferson has not been charged with any crime and has maintained he is innocent, saying he has not yet had a chance to put forward his side of the story.

Earlier this week, U.S. Attorney General, Alberto Gonzalez said that while a search of a lawmaker's congressional office was unique, the Justice Department was compelled by the refusal of Jefferson to comply with a subpoena.

"The Department of Justice is doing its job in investigating criminal wrongdoing, and we have an obligation to the American people to pursue the evidence where it exists," said Alberto Gonzalez.

In an unusual joint statement Wednesday, House Speaker Hastert and Democratic Leader Nancy Pelosi accused the Justice Department of violating the principle of Separation of Powers, and the Speech or Debate Clause of the U.S. Constitution which provides immunity to lawmakers while they are engaged in legislative acts.

They say that while these principles were not designed to place anyone above the law, they were designed to protect the Congress and the American people from abuses of power.

The Republican and Democratic leaders also demand that the Justice Department return papers that were unconstitutionally seized and that federal authorities stop any review of documents, and ensure that contents are not revealed to investigators.

Though House Democrats have not called publicly for Congressman Jefferson to resign his seat in the House, Minority Leader Pelosi Wednesday took the step of asking him to resign immediately from a key House committee. Jefferson has refused.