WASHINGTON — In unusually blunt terms, Defense Secretary Robert Gates on Monday challenged the Air Force, whose leaders are under fire on several fronts, to contribute more to immediate wartime needs and to promote new thinking.

Gates singled out the use of pilotless surveillance planes, in growing demand by commanders in Iraq and Afghanistan, as an example of how the Air Force and other services must act more aggressively.

Gates has been trying for months to get the Air Force to send more unmanned surveillance and reconnaissance aircraft, like the Predator drone that provides real-time surveillance video, to the battlefield. They are playing an increasing role in disrupting insurgent efforts to plant roadside bombs.

"Because people were stuck in old ways of doing business, it's been like pulling teeth," Gates said of his prodding. "While we've doubled this capability in recent months, it is still not good enough."

Pentagon press secretary Geoff Morrell said Gates' complaint about struggling to get more drone aircraft to the battlefield was aimed not only at the Air Force but at the military as a whole.

Gates made his remarks to a large group of officers at the Air Force's Air University at Maxwell Air Force Base, Ala. Noting that they represent the future of Air Force leadership, he urged them to think innovatively and worry less about their careers than about adapting to a changing world.

Later, Gates flew to the U.S. Military Academy at West Point, N.Y., to deliver a speech to cadets and faculty members. He encouraged young soldiers to "take on the mantle of fearless, thoughtful but loyal dissent" when the situation calls for it, and to "defend your integrity as you would your life," according to a text of his prepared remarks released in advance by the Pentagon.

He alluded to a controversial article published last May in the Armed Forces Journal in which the author, Army Lt. Col. Paul Yingling, wrote that America's generals had failed the nation by not properly preparing the armed forces for war in Iraq and by not accurately portraying to the public how the war was unfolding.

Gates said he was impressed that the Army allowed that critique to be published.

"I believe this is a sign of institutional strength and vitality," Gates said.

Gates also said the Iraq war is a "hard sell" for continued support from the American public, and he warned in strong terms of the consequences of getting into an armed conflict with Iran.

"Another war in the Middle East is the last thing we need and, in fact, I believe it would be disastrous on a number of levels," he said in his prepared remarks. He called Iran "hell bent" on acquiring nuclear weapons and said that as a result he favors keeping the military option on the table.

At Maxwell, Gates did not mention any of the controversies that have dogged the Air Force in recent months — most recently the disclosure that investigators had found that a $50 million contract to promote the Air Force's Thunderbirds aerial stunt team was tainted by improper influence and preferential treatment. The probe found no criminal conduct but laid out a trail of communications from Air Force leaders — including from its top officer, Gen. Michael Moseley — that eventually influenced the 2005 contract award.

The Air Force also has been involved in a pair of embarrassing nuclear-related mistakes, and Air Force Secretary Michael Wynne, the service's top civilian, was compelled to issue a public statement last month disowning a public remark by a senior general that suggested the Air Force was at odds with the Bush administration over money in the proposed 2009 budget for F-22 stealth fighters.

The bulk of Gates' remarks focused on suggested areas in which the Air Force can adapt to changing times.

While Gates' comments were directed mainly at the Air Force, his concern about faster fielding of unmanned surveillance and reconnaissance aircraft included a broader appeal to the entire military. The Army, Navy and Marine Corps have been expanding their fleets of drone aircraft.

"In my view we can do and we should do more to meet the needs of men and women fighting in the current conflicts while their outcome may still be in doubt," he said. "My concern is that our services are still not moving aggressively in wartime to provide resources needed now on the battlefield."

He cited the example of drone aircraft that can watch, hunt and sometimes kill insurgents without risking the life of a pilot. He said the number of such aircraft has grown 25-fold since the terrorist attacks of Sept. 11, 2001, to a total of 5,000.

To push the issue harder, Gates said he established last week a Pentagon-wide task force "to work this problem in the weeks to come, to find more innovative and bold ways to help those whose lives are on the line."

Pentagon spokesman Bryan Whitman said Gates expects an initial report from the group by early May.

Gates likened the urgency of the task force's work to that of a similar organization he created last year to push for faster production and deployment of mine-resistant, ambush-protected armored vehicles that have been credited with saving lives of troops facing attacks by roadside bombs in Iraq.

"All this may require rethinking long-standing service assumptions and priorities about which missions require certified pilots and which do not," Gates said, referring to so-called unmanned aerial vehicles in the Air Force fleet that are controlled by service members at ground stations.

Gates, who served in the Air Force in the 1960s as a young officer before he joined the Central Intelligence Agency, urged the officers in his audience to dedicate themselves to thinking creatively.

"I'm asking you to be part of the solution and part of the future," he said.