Committee spokesman Ken Johnson said Andersen, which now faces a federal obstruction of justice trial, delivered the "broadly worded" subpoena seeking materials related to the House investigation of Enron's bankruptcy - the largest in U.S. history - and Andersen's role as the energy giant's accounting firm.

"We're fighting it," Johnson said. "First of all, the world knows what David Duncan told us. The summary of his testimony, which was made public, pretty accurately reflects what he told our investigators. The notion that we're holding something back is ridiculous."

Johnson said that provisions in the U.S. Constitution's "speech and debate" clause, which protects statements made in Congress, provides sufficient legal grounds for a judge to dismiss the subpoena.

A federal grand jury in March indicted Anderson on a single obstruction of justice charge, claiming that the firm launched a broad, highly organized effort to destroy Enron-related documents and computer disks after learning that Enron was under federal investigation.

Andersen has argued that Duncan, a lead partner in its Houston office, acted without authority from Andersen's Chicago headquarters. Andersen's trial on the obstruction charge is scheduled to begin Monday in Houston.

Andersen attorney Stanley Brand said the subpoena was aimed at "exculpatory statements" Duncan made to House committee investigators that may show that Duncan acted without authority from Andersen executives.

He said there have been previous cases in which political figures were forced to turn over documents they claimed were privileged.

"Under the U.S. versus (Richard) Nixon, even the president's conversations had to be turned over to a judicial procedure," Brand said.

Andersen's shredding of Enron material took place in late October 2001, days after Enron announced a charge against earnings of $618 million, and after the company learned that it was the subject of a U.S. Securities and Exchange Commission inquiry.

Enron filed for bankruptcy on Dec. 2, and later revealed that it has used a series of outside partnerships to shift and conceal its building debt.

Earlier this year, Duncan, who was Andersen's lead partner on the Enron account in Houston, met with House Energy committee investigators for four hours to discuss the shredding operation.

On Jan. 24, Duncan appeared before a House Energy subcommittee, but invoked his Fifth Amendment right against self-incrimination.

Minutes later, Rep. James Greenwood, R-Pa., chairman of a House subcommittee on investigations, summarized Duncan's earlier statements to committee investigators.

In particular, Greenwood noted that Duncan had received a call from an Andersen corporate attorney reminding him of the firm's document management procedures, which requires the destruction of all unnecessary client documents. Duncan, Greenwood related, told investigators that he was following Andersen's policies when he organized the document destruction effort.

Greenwood could not be reached for comment Tuesday.

Brand said that it was Greenwood's account of Duncan's statements to investigators that prompted the Andersen legal team to issue its subpoena, though he declined to say what portion of the statement was of interest.

"In a normal criminal context, based on what Chairman Greenwood proffered, his (Duncan's) statements are exculpatory, and a defendant has a right to those statements," Brand said. "There are part in there that, if you read them in the context in which they were made, tend to exculpate Andersen. There's a bunch of them."

Duncan pleaded guilty April 9 to federal obstruction of justice charges.