ABOARD A U.S. MILITARY AIRCRAFT OVER THE PACIFIC >> Defense Secretary Leon Panetta said the Obama administration is nearing a decision in the next few weeks on how many U.S. troops would remain in Afghanistan — and for what purposes — after the U.S.-led combat mission ends in 2014.

Panetta told reporters aboard his plane en route from Hawaii to Australia that Gen. John Allen, the top U.S. commander in Afghanistan, has developed several options on a post-2014 presence.

Panetta also was asked about his future at the Pentagon. While he declined to reveal his plans, he suggested he still had work to do on the job he took in July 2011.

“It’s no secret that at some point I’d like to get back to California,” he said. Panetta is from Monterey, California.

He added that there are a number of important defense issues awaiting resolution, including a budget impasse and the future of U.S. involvement in Afghanistan — suggesting that he would not leave immediately.

“Right now, my goal is to basically meet my responsibilities with regard to dealing with those issues,” Panetta said.

Pressed to say whether he would rule out staying for all four years of a second Obama term, he replied, “Who the hell knows?”

Panetta said the Pentagon is reviewing those options with the White House. He would not reveal what troop levels are being considered, but it is believed that at least several thousand could be needed for several years beyond 2014.

“My hope is that we’ll be able to complete this process in the next few weeks,” Panetta said.

The decision will depend in part of the Afghan government’s willingness to permit a post-2014 U.S. military presence and to provide legal guarantees for those troops that are acceptable to Washington.

Once that decision is made, U.S. officials have said they will set a timetable for reducing troop levels between now and the end of 2014. There now are about 67,000 U.S. troops in Afghanistan, and their mission is evolving from combat to advising, assisting and training Afghan forces.

A post-2014 U.S. military presence also would be expected to include hunting and killing extremists, including members of al-Qaida in Afghanistan.

Asked about David Petraeus’s resignation as CIA director over revelations that he had an affair with his biographer, Panetta said he saw it as a “very sad situation to have him end his career like that.” Panetta was CIA director before Petraeus.

“I think he took the right step” by resigning, Panetta added.

Panetta was beginning a weeklong trip to Asia to meet with his counterparts in Australia, Thailand and Cambodia. He said this was an important expression of the Obama administration’s commitment to deepening ties in the region and developing more security partnerships.

For decades American administrations have fought the perception among Asians that Washington paid too little attention to their security interests. This view was reinforced during the years of U.S. focus on Iraq, and it persists even as the war in Afghanistan winds down.

The Obama administration has made much of its “pivot” to the Asia-Pacific, which has entailed more high-level diplomatic and security engagements and an attempt to expand cooperation with Australia and others in the region. But it is not fundamentally different from what the administration of President George W. Bush was pursuing even as it got mired in Iraq and saw stalemate in Afghanistan.

In June 2007, then-Defense Secretary Robert Gates argued at a security conference in Singapore that the U.S. was increasingly focused on Asia.

“Far from neglecting Asia, the U.S. is more engaged than ever before,” he said. “We have been extraordinarily busy in recent years as we reshape and strengthen our security ties based on shared interests. Some are bilateral relationships that have been formed, renewed, or modernized – each with varying types and degrees of cooperation.”

Among the issues dogging Panetta and the Pentagon is the controversy over the U.S. response to an attack on U.S. diplomatic facilities in Benghazi, Libya, two months ago.

Panetta said the Pentagon and the State Department are assessing what additional or improved arrangements might be necessary to secure U.S. diplomatic outposts in the Middle East. He was not specific.

As for the Benghazi attack, Panetta said it was “largely over” by the time the Pentagon was able to move forces close enough to Libya to respond.

Asked about the prospect of Congress and the administration settling for a short-term fix to the budget deficit crisis, rather than agreeing on measures to end the threat of further large defense spending cuts, Panetta said, “That’s the worst thing that could happen.”

He added: “That’s the last damn thing I need right now,” because it would perpetuate uncertainty about future defense spending and defense priorities.