A top Air Force general became the first uniformed victim of his service's contracting scandal, withdrawing his nomination for one of the highest positions in the military last night a few hours after a tumultuous confirmation hearing before the Senate Armed Services Committee.

Air Force Gen. Gregory S. Martin had been nominated by the Bush administration to be the new U.S. commander for the Pacific and East Asia, a position that oversees operations in more than half the globe.

Martin "has requested that his nomination for commander, U.S. Pacific Command, be withdrawn," the Pentagon said in a two-sentence statement issued last night.

It followed by a week the revelation that another senior Air Force officer, Maj. Gen. Thomas J. Fiscus, the service's top uniformed lawyer, had stepped aside temporarily while he is under investigation for, among other things, allegedly having an inappropriate sexual relationship with a subordinate.

Martin's move came after a day in which members of the Armed Services panel also criticized President Bush's nominee for Army secretary as lacking the background needed to oversee the Army as it engages in Iraq in the first sustained combat operations it has faced since the Vietnam War.

Two Republican senators led the charge against the nominees proposed by the Republican White House.

Sen. John McCain (Ariz.) vociferously challenged Martin, the first Air Force officer ever tapped for the command of U.S. forces in the Pacific, which for decades has been seen as a Navy possession. McCain is a retired Navy officer and the son of Adm. John S. McCain Jr., the U.S. commander in the Pacific from 1968 to 1972.

McCain attacked Martin not on that basis, but because Martin has been intimately involved in Air Force acquisition issues for years. Now chief of the Air Force Materiel Command, Martin earlier in his career worked closely with Darleen A. Druyun, a former Air Force procurement official who last week was sentenced to nine months in prison for granting favors in contracts to Boeing Co. before going to work there.

McCain has been locked in a fight with the Air Force over its plan to spend billions to acquire new refueling aircraft from Boeing. "In response to repeated requests by Congress for tanker-related records, the Air Force stonewalled for months," he said, and then under threat of subpoena produced documents "only after doctoring" them.

"In my 22 years in Congress, it's the most frustrating thing that I've ever seen," he said.

Martin said he is not an expert in contracting but would have "raised the flag" had he seen Druyun do anything illegal. "When she made her plea bargain, not only was I disappointed, but I was very surprised," he said.

Unsatisfied, McCain indicated that he would keep Martin's nomination bottled up in the committee until the Air Force turns over all the documents he has requested. Sen. John W. Warner (R-Va.) appeared to back that position, saying he would withhold his support until the committee completes its work on the refueler aircraft issue.

A spokesman for Warner declined to comment on Martin's withdrawal from consideration. Neither McCain nor his spokeswoman could be reached.

Martin was born on Fort Myer and attended the Landon School in Bethesda, from which he graduated in 1966. After finishing at the Air Force Academy in 1970, he flew 161 combat missions in the Vietnam War. He later commanded a variety of fighter aircraft units before moving into some top-level jobs in Air Force acquisition. In 2000, he became head of the Air Force in Europe, and in 2003 he took over as chief of the Air Force Materiel Command, which has its headquarters at Wright-Patterson Air Force Base in Ohio.

At the confirmation hearing, Warner also expressed concern about the credentials of Francis J. Harvey, who was nominated to fill the vacancy created when Defense Secretary Donald H. Rumsfeld fired Thomas E. White as Army secretary 17 months ago, just after the end of the spring 2003 invasion of Iraq.

Warner and other panel members questioned how well Harvey's background as an engineer and executive at Westinghouse Electric Corp. and Duratek Inc. had prepared him to handle the human side of the Army at a time when it is under stress.

"We will very carefully scrutinize your qualifications," Warner said.

Senators pressed Gen. Gregory S. Martin about the tanker contract.