At a Pentagon press briefing, Dempsey said repositioning forces to the Asia Pacific is not the "essence of rebalancing" to that region, which the Obama administration is doing as the wars in Iraq and Afghanistan wind down.

He said the strategy involves "three mores," including more interest, more engagement and more quality, and the U.S. side is eyeing a troops presence there more at a rotational basis, rather than at permanent bases.

Fresh off an Asian tour which included stops at Singapore, Thailand and the Philippines, Dempsey said regional countries mostly gave "positive feedback" to that approach, and the U.S. side wants them to take a bigger share of the burden.

"We're encouraging ASEAN [the Association of Southeast Asian Nations] to take a more active role, to be a unified voice for security issues in that region," he said.

Dempsey is part of the Department of Defense delegation to the Shangri-La Dialogue in Singapore, and he went solo to Thailand and the Philippines after that, as Defense Secretary went on to visit Vietnam, India and Afghanistan.

The U.S. military is facing mounting pressure to cut back on expenses, and the Pentagon is cutting 487 billion dollars of military budget over the next 10 years. If Congress fails to act this year, automatic cuts totaling 600 billion will kick in next year, further straining the military's ability.

The U.S. side has insisted budget related to the rebalancing effort won't be cut, however, Dean Cheng, a research fellow at Heritage Foundation, cautioned that the vastness of the Pacific could put more burden on a military already stretched thin, as more exercises and ship visits mean more wear and tear on ship hulls and aircraft airframes. It also means more time away from home for service people, threatening to weaken readiness, maintenance, training and retention.