Perle said he would remain a member of the Defense Policy Board while stepping down as chairman, and quit his consulting job with Global Crossing.

“As I cannot quickly or easily quell criticism of me based on errors of fact concerning my activities, the least I can do under these circumstances is to ask you to accept my resignation as chairman of the Defense Policy Board,” Perle wrote to Defense Secretary Donald Rumsfeld.

Rumsfeld accepted Perle’s resignation as chairman but asked that he remain a member of the board, and Perle said in a telephone interview that he agreed to stay on the board.

“He has been an excellent chairman and has led the Defense Policy Board during an important time in our history,” Rumsfeld said in a statement. “I should add that I have known Richard Perle for many years and know him to be a man of integrity and honor.”

In a letter to Chris Nash, a senior vice president at Global Crossing, Perle wrote: “In light of the recent controversy reported in the press, I think it best that I withdraw from performing any further services for the company. I believe most of my work on your behalf is complete.”

On Monday, Rep. John Conyers, a Michigan Democrat, asked the Pentagon’s inspector general to probe Perle’s work as a paid adviser to Global Crossing and his guidance on investment opportunities resulting from the Iraq conflict.

Conyers said on Thursday Perle’s continued membership on the Pentagon panel was problematic. “I have no plans to withdraw my request for a review of Mr. Perle’s conflicts of interest by the Defense Department inspector general,” he said.

In his resignation letter, Perle said, “I am advising Global Crossing that I will not accept any compensation that might result from their pending acquisition and that any fee for past service would be donated to the families of American forces killed or injured in Iraq.”

Perle said by telephone that the $125,000 fee received for work he had already done for Global Crossing would be donated. He had said previously that he would have been paid another $600,000 if the government approved the deal.

Perle agreed to help Global Crossing, a bankrupt operator of an international fiber-optic network, win US approval to sell a 61.5 percent stake to Hutchison Whampoa Ltd. and Singapore Technologies Telemedia Pte.

The deal ran into problems with the Committee on Foreign Investment in the United States, which counts Rumsfeld and other top US national security advisers as members.

The committee can block mergers and acquisitions it feels could harm US interests, and it raised concerns that Global Crossing’s network would be controlled by a company with strong ties to China. Hutchison is majority-owned by Hong Kong’s richest man, Li Ka-shing.

As chairman of the Defense Policy Board, created in 2001 to advise the Pentagon, Perle had no official policymaking role and was not paid. He has been influential in developing the Bush administration’s plan to oust Iraqi President Saddam Hussein