Defense Secretary Leon Panetta remarks reflect a growing sentiment within the Obama administration that its approach to Iraq may provide a useful model for winding down operations in Afghanistan. (Jacquelyn Martin/AP)

The United States hopes to end its combat mission in Afghanistan by the middle of next year, more than a year earlier than scheduled, Defense Secretary Leon E. Panetta said Wednesday.

His remarks reflected a growing sentiment within the Obama administration that its approach to Iraq, where the official end of U.S. combat operations came 16 months before the final U.S. troop withdrawal in December, may provide a useful model for winding down operations in Afghanistan.

Current NATO strategy, agreed to at a summit in Lisbon in November 2010, calls for coalition forces to gradually shift to a training, advisory and assistance role with the Afghan military on the way to withdrawing all combat troops by the end of 2014.

The alliance has yet to agree on the pace of that process, however, and Panetta went further than what some in the administration were prepared to say publicly about their own deliberations. “Our goal is to complete all of that transition in 2013,” Panetta told reporters en route to a meeting of NATO defense ministers in Brussels. “Hopefully by mid- to the latter part of 2013 we’ll be able to make a transition from a combat role.”

NATO “consultations are ongoing,” said a U.S. official, who spoke on the condition of anonymity to clarify the administration’s position. “Until the leaders come together . . . and make a final decision” at their scheduled May summit in Chicago, “nothing is final.”

A Panetta spokesman traveling with the defense chief issued a statement Wednesday evening — several hours after Panetta’s original remarks — saying that U.S. troops could still be involved in at least some combat operations, in partnership with Afghan forces, in 2014.

Afghan officials were unfazed by Panetta’s statements, saying they were confident that the United States would remain a stabilizing force in Afghanistan and that the country’s own army and police will be ready to accept a more active role in the conflict by 2013.

“The international troops are focusing more on the strengthening, equipment and funding of Afghan forces, and this will make the Afghan forces self-sufficient and ready to take on this big responsibility,” said Hakim Asher, a government spokesman. He called the statement a “natural part of the process of transition.”

But Panetta’s comments about an accelerated change in the military mission were the latest sign that the United States and its NATO allies are seeking to hasten the end of their involvement in the unpopular, decade-long war. On Friday, French President Nicolas Sarkozy, facing a tough reelection campaign, abruptly announced in Paris that his country would speed up its combat drawdown this year.

Panetta, in his remarks en route to the NATO meeting, emphasized that an early transition did not mean early withdrawal, saying, “We’ve got to stick to the Lisbon strategy.”

U.S. and NATO forces, he said, would still be actively engaged in helping Afghan forces operate. Although the Afghan army has grown in size and capability, it is still dependent on the U.S. military for air power, troop movement, supplies and medical aid.

“It’s still a pretty robust role that we’ll be engaged in,” Panetta said. “That doesn’t mean that we’re not going to be combat-ready.”

As long as U.S. troops of any kind remain in Afghanistan, the accelerated timetable is unlikely to mollify Islamic militants fighting the governments of Afghanistan and Pakistan, some analysts say.

“Whether it is the Pakistani Taliban, the Afghan Taliban or al Qaeda, the narrative is the same: they want to liberate Afghanistan from foreign occupation,” said Pakistani author Imtiaz Gul, executive director of the Center for Research & Security Studies in Islamabad. “The first major hurdle the U.S. and coalition forces face is opposition to the U.S. bases in Afghanistan. The Taliban have taken the maximalist position that foreign forces must leave lock, stock and barrel.”

President Obama has yet to decide how many troops will stay in Afghanistan and for how long. Existing withdrawal plans call for the number to decline from the current 90,000 to 68,000 by September, a level at which military commanders — with Panetta’s backing, according to defense officials — would like it to remain until the end of 2014.

The administration is also negotiating an agreement with the Afghan government for what Panetta called an “enduring presence” of counterterrorism and training forces that would remain indefinitely.

The administration tried but failed to negotiate a similar long-term agreement with Iraq.

Although Afghanistan has not played a prominent role so far in the U.S. presidential campaign, former Massachusetts governor Mitt Romney, the front-runner for the GOP nomination, has said he wants to continue fighting the Taliban until it is defeated. He has criticized Obama’s strategy of battling the insurgents while also engaging them in talks.

The Obama administration is betting that Americans are tired of the financial and human cost of the war and would welcome an exit strategy so long as they believed it ensured U.S. national security. Obama has asserted that the completion of the phased Iraq withdrawal, promised during his 2008 campaign, is evidence of U.S. strength and his own resolve.

Although he announced the official end of U.S. combat operations in Iraq in August 2010, many of the 50,000 troops that remained continued to engage in combat, in partnership with the Iraqi troops and occasionally without them.

In addition to the human toll, the fiscal cost of the Afghanistan conflict has weighed heavily on all members of the coalition. Panetta said he would ask other NATO defense ministers to reconsider whether it still made sense to underwrite the expansion of Afghanistan’s national security forces, currently at about 310,000 members, to a planned total of 350,000 soldiers and police.

Boosting the size of the Afghan force has been a cornerstone of the NATO strategy for the war. But the alliance has been reconsidering whether it can still afford to subsidize such a large Afghan force, and for how long. Administration officials have said that Washington and allied capitals can expect to pay for the bulk of the expense of equipping and training Afghan forces long after 2014.

“There’s a general understanding that if this is going to remain sustainable, it may need to come down a little bit,” said a senior U.S. defense official, speaking on the condition of anonymity under ground rules set by the Pentagon. “Exactly what the figure is and what the precise timing will be is something we need to discuss with our allies.”

Panetta said the United States and NATO would ask Arab allies, Japan, South Korea and other countries to pitch in to subsidize the Afghan army and police over the long term.

“In many ways, the funding is going to determine what kind of force we can sustain for the future,” he said.

Under the existing NATO plan, agreed to with Afghan President Hamid Karzai in Lisbon, Afghan security forces are scheduled to take control of military operations in about half the country sometime this year, with the rest to gradually follow before the end of 2014.

Although Karzai has expressed public displeasure with NATO forces repeatedly since then, it is unclear whether he has participated in or been briefed on the new plans being discussed.

DeYoung reported from Washington. Correspondents Richard Leiby in Islamabad, Pakistan and Kevin Sieff and Sayed Salahuddin in Kabul contributed to this report.