With US troops pulling out of Iraq and drawing down in Afghanistan, the US military hopes to shift its focus towards Asia, a strategic priority for Washington despite intense budget pressures.

In his first trip to the Asia-Pacific region since taking over at the Pentagon, Defense Secretary Leon Panetta repeatedly made the point last month that the United States was at a "turning point" after 10 years of war.

"We have the opportunity to strengthen our presence in the Pacific. And we will," he said during a stop in Japan.

The message conveyed to allies and partners in the region was clear, Panetta said in a note to Defense Department employees: the United States is "committed to sustaining and enhancing our military presence in the region."

The US pledges are designed to allay the concerns of allies who face an increasingly powerful and assertive China as well as an unpredictable and volatile regime in North Korea.

"There is a concern in Asia that as China gets stronger that somehow is going to force the United States out, and I think what the US is trying to do is reassure people that it has no plans on leaving," Ralph Cossa, president of the Pacific Forum CSIS in Honolulu, told AFP.

The end of the US troop presence in Iraq by the end of the year and plans to gradually withdraw from Afghanistan by 2015 has opened the way for the pivot towards Asia and the Pacific, officials say.

Secretary of State Hillary Clinton, writing in Foreign Policy magazine, said President Barack Obama set "a strategic course" to concentrate on Asia at the outset of his administration.

The pair will seek to cement Washington's clout in Asia this week at a summit of Pacific Rim economies in Hawaii, and are hoping that a sweeping regional trade pact will help bind the region together.

Panetta's trip to key security allies Japan and South Korea as well as Indonesia is part of a high-level US engagement with Asia which will extend into the 18-nation East Asia Summit on the Indonesian resort island of Bali which Obama will also attend later this month

But for Cossa, "the reality is US foreign policy in Asia has remained pretty consistent over both Republican and Democratic administrations."

"It's focused on maintaining the alliances, promoting partnerships, promoting cooperation and free trade and that really hasn't changed," he said.

Panetta has promised that the US military role in the Pacific will be spared from planned defense budget reductions of more than $450 billion over the next ten years.

But there are no signs the US military plans to dramatically expand its presence in the Pacific either.

About 85,000 military personnel are deployed in the region, mostly in Japan and South Korea, even as the US Army as a whole anticipates downsizing its force in coming years.

The US Navy has already cut back its fleet of ships, from 320 in 2001 to 284, and some analysts, including retired general David Barno of the Center for a New American Security, have raised the possibility of eliminating one of the country's 11 aircraft carriers to save costs.

In the Pacific, about 50 US naval ships are criss-crossing the ocean at any given time while the aircraft carrier USS George Washington and 18 other ships are based out of Japan.

Asked about assigning additional assets to the Pacific region, the Pentagon chief has offered few details and only spoken generally of strengthening the capabilities of allies and conducting joint exercises.

The United States could also decide to "forward deploy" more ships and hardware in Asia, according to senior officers, a move that saves fuel costs while increasing the military's profile.

As an example, officials cite plans announced earlier this year to deploy some of the new US littoral combat ships to Singapore.

"The Chinese will say, America is building up because of us and the point is we're really not building up," Cossa said. "We're consolidating, we're keeping the core but it's not that we're rushing forces to Asia."