Facing questions that he brushed off advice from generals and underestimated the troops needed to attack Iraq, Defense Secretary Donald H. Rumsfeld called his critics "second-guessers" who fail to appreciate the war's success so far.

"It's a little early for post-mortems. It's a little early to write history," the defense secretary said Sunday, nine days after the attack on Iraq began.

It is not the first time that Rumsfeld, a former fighter pilot with a confident and sometimes-combative style, has faced criticism that he is too quick to dismiss the views of others, including the top generals who advise him.

He was quick Sunday to rebut such charges, insisting the Iraqi strategy had originated with war commander Gen. Tommy Franks and had been approved through the nation's military command, all the way up to President Bush.

Asked about the criticism during an appearance on ABC's This Week, Rumsfeld replied: "What you're seeing is fiction. You're seeing second-guessers out there."

"In fact, the president wanted to support the diplomacy in the United Nations. So he wanted things to flow in over a period of time," Rumsfeld said, in reply to questions about whether troops and equipment moved too slowly to Iraq.

"But everything that they've [ground commanders]asked for is in process. It's all arriving," Rumsfeld said.

Last week, the Army's senior ground commander in Iraq, Lt. Gen. William S. Wallace, said the resistance of Iraqi fighters had been a surprise, although he said the war still was on track.

Wallace told reporters: "The enemy we're fighting is different from the one we'd war-gamed against."

Both Rumsfeld and the nation's top general, Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff, have said in recent days that any U.S. ground commander or soldier who expresses surprise at Iraqis' ferocity is seeing only one part of the war, not the overall situation.

But a Republican senator, Chuck Hagel of Nebraska, while not mentioning Rumsfeld by name, said he was "a little concerned" that Pentagon civilian leaders aren't listening enough to such views.

"When your battlefield commanders — who are there, who are commanding the troops in the middle of the battle — are saying certain things, the civilian leadership at the Pentagon must be very careful not to be publicly dismissive of that," Hagel said on CNN's Late Edition.

During his first months as defense secretary, before the Sept. 11 terrorist attacks, Rumsfeld angered some Pentagon generals and members of Congress with his forceful style.

They accused him of failing to consult generals or Congress as he pushed for unpopular proposals to "transform" the military and close military bases.

Once the war in Afghanistan began, however, Rumsfeld's frequent appearances at televised Pentagon briefings made him so popular that Bush once jokingly called his 70-year-old defense secretary a "sex symbol."

A Gallup poll earlier this year indicated nearly 6 in 10 Americans had a favorable opinion of Rumsfeld.

But in recent days, retired generals including Barry McCaffrey, a ground commander during the 1991 Persian Gulf War, have insisted that Rumsfeld dangerously ignored advice that the ground troops in Iraq were stretched too thin.

Rumsfeld said he could think of only one instance, during the prewar troop and equipment buildup, when he questioned war planners about their recommendation to call up one particular unit, as opposed to letting somebody else handle the job.

Rumsfeld also insisted the decision to skip a lengthy air war before the ground war helped avert humanitarian disasters and save Iraq's oil fields.

"A lot of good things happened, and a lot of bad things were avoided, because General Franks decided to put forces on the ground fast and early," Rumsfeld said.