The Los Angeles-class fast-attack submarine USS Chicago arrives at Naval Base Guam after completing a change of homeport from Pearl Harbor, Hawaii, in this April 2012 photo.

HONOLULU — A fourth attack submarine will be sent to Guam and six destroyers will be shifted from duty in Europe to the Asia-Pacific as part of the re-balancing of U.S. forces that's taking place in the region, a top Pentagon official said Monday.

Deputy Secretary of Defense Ashton Carter outlined those steps and a host of others after returning from a trip to Japan, South Korea, the Philippines and Indonesia.

Part of the purpose of the trip was "to make sure that our forces, our allies and our partners in the region understand that we are serious about our defense commitments there — that we are going to walk the walk, not just talk the talk," Carter said in remarks prepared for a speech at the Center for Strategic and International Studies in Washington.

The United States has embarked on a "great strategic transition" with the Iraq War over and Af­ghani­stan winding down, Carter said. "We are turning a strategic corner and focusing our attention on the challenges and opportunities that will define our future," he said.

Former Defense Secretary Leon Panetta announced last year that 60 percent of U.S. Navy assets would be assigned to the Asia-Pacific region by 2020.

The Navy will be permanently basing four destroyers in Rota, Spain, to provide ballistic missile defense to European allies. Previously, that mission was performed by 10 destroyers rotating from the United States to the Mediterranean.

"The six destroyers that will now be released will be able to shift their deployments to the Asia-Pacific region while the four ships in Spain continue providing the same amount of missile defense coverage for our European allies," Carter said.

With the drawdown in Af­ghani­stan, the Navy will be "releasing" naval surface combatants as well as intelligence, surveillance and reconnaissance assets for Asia-Pacific use.

Already, EP-3 signals reconnaissance aircraft have moved from U.S. Central Command to U.S. Pacific Command, Carter said.

Destroyers and amphibious ships that conducted security cooperation and humanitarian assistance in Africa, South America and Europe will be replaced in those missions by joint high-speed vessels and littoral combat ships, freeing the bigger warships to deploy to Asia and the Pacific.

"It's been widely discussed that there would be a 60-40 split between the Pacific and Atlantic naval forces, and I think what you are seeing is that as planning works through the process, some of that is now coming to fruition," said Lt. A.J. Falvo, a spokesman for U.S. Pacific Fleet at Pearl Harbor.

Carl Baker, director of programs for the Pacific Forum Center for Strategic and International Studies in Hono­lulu, said he expects the number of attack submarines and surface warships in Hawaii to grow.

"I'm sure Washington (state) and San Diego will get their fair share of this whole redeployment west, but the fact is that Hawaii is a much better location," Baker said. "You save yourself a couple days (sailing time) by putting them here, and so, with the infrastructure in place, I see that Hawaii will become more important."

Guam is "only so big, and there's only so many berths for ships in Guam," Baker said.

The Navy will add a fourth attack submarine to Guam in 2015, Carter said. Firescout unmanned aerial vehicles and P-3 Orion maritime patrol aircraft will be shifted from Afghanistan to U.S. Pacific Command.

The Air Force will be able to send MQ-9 Reaper, U-2 and Global Hawk aircraft to the region and allocate space, cyber, tactical aircraft and bomber forces to the Asia-Pacific with little new investment as 60 percent of its overseas-based forces are already based here, Carter said.

At least 2,700 more Marines will come to Hawaii, and more helicopters and Osprey tilt-rotor aircraft are being sent here. With duty in Af­ghani­stan ending, U.S. Pacific Command is regaining control of Army soldiers who will focus on training with allies, Carter noted.

Carter said the Pentagon has the resources to accomplish the re-balancing, even though some point to the "seemingly endless debate in Washington about the U.S. budget."

"I'm interested to hear this because I'm more accustomed to listening to people question why the U.S. spends more on defense than the next 16 largest militaries in the world combined," Carter said. "That statistic is true and won't change much in coming years."

