Congressional investigators will subpoena senior officials of the Arthur Andersen auditing firm, including the chief executive and a fired auditor, in an effort to force their testimony Thursday in the Enron controversy.

Ken Johnson, spokesman for the House Energy and Commerce Committee, said the panel's chairman, Rep. Billy Tauzin, R-La., would sign the four subpoenas Tuesday night.

Subpoenas are going to Andersen CEO Joseph Berardino, fired auditor David Duncan, attorney Nancy Temple and risk manager Michael Odom.

Duncan was dismissed by Andersen last week for his role in the extensive destruction of Enron-related documents after federal regulators began investigating possible irregularities in the failed energy company's accounting.

Through his lawyers, he has asked for a delay in his testimony to review documents and prepare for the congressional hearing. Duncan already has talked to committee investigators.

Robert Giuffra, one of his attorneys, said Tuesday evening that no decision had been made on whether Duncan would testify. "We have not received a subpoena," he said.

Temple and Odom, while expressing willingness to testify, have raised concerns about protecting confidential information relating to the investigation, Johnson said.

He noted that the firm's chairman had been interviewed over the weekend on television.

"Mr. Berardino found the time to brief the American public on Meet the Press on Sunday," Johnson said. "He should be able to find the time to appear at a congressional hearing."

Patrick Dorton, an Andersen spokesman, said, "We have not received a subpoena. We have told the committee that we would testify but the only question is when."

News of the planned subpoenas came as FBI agents and federal prosecutors entered Enron's Houston headquarters to investigate allegations that massive document destruction took place at the company starting after Thanksgiving and continuing until as recently as last week.

The Securities and Exchange Commission started looking into Enron's accounting in mid-October, after the company reported a third-quarter loss of more than $600 million. The SEC's inquiry eventually included demands for financial documents from Enron and Andersen.

Enron entered the largest bankruptcy in U.S. history on Dec. 2.

The Energy and Commerce panel is one of two committees holding Enron hearings on Thursday. The Senate Governmental Affairs Committee is calling officials from the SEC, the Federal Energy Regulatory Commission and the Commodity Futures Trading Commission to determine whether regulators missed signs of trouble at Enron.

In another development Tuesday, Sen. Phil Gramm, one of Congress' biggest recipients of Enron campaign donations, has decided to remove himself from part of the wide-ranging congressional investigations.

Gramm will be absent from hearings focusing on what went wrong at Enron but will take part in more general inquiries into accounting standards, investor protection issues and other matters, spokesman Larry Neal said.

In a sprawling inquiry with both financial and political overtones, 11 House and Senate committees are investigating the Enron debacle, while the Justice Department and the SEC pursue their own less visible probes.

President Bush urged Congress on Tuesday not to be distracted by the Enron investigation.

"I'm confident that all the facts will come out on Enron. And I'm also confident that if Congress has the right attitude, we can get a lot done," Bush said in a pitch for his economic revival plan.

He said his mother-in-law, Jenna Welch, had lost about $8,000 on an investment in Enron stock.

"A lot of the stockholders didn't know all of the facts. And that's wrong," said Bush.

The president has received large political contributions over the years from Enron Chairman Kenneth Lay, who is expected to testify before two congressional committees on Feb. 4.

Bush said Tuesday that officials in his administration had done "the exact right thing" in response to Enron's pleas for help as the company was collapsing last year. Treasury Secretary Paul O'Neill and Commerce Secretary Donald Evans have said they received calls from Lay but took no action.