There are about 17,000 Marines on Okinawa, and another 4,000 on the Japanese Mainland. The Corps has faced growing Japanese concern over noise, air crashes and crime.

Complaints from Okinawa, where homes have encroached on bases such as Marine Corps Futenma Air Station, have sharpened the discussion about the Marine presence on the island. This comes at a time when the United States looks at realigning its forces in East Asia.

The Aug. 13 crash of a CH-53D Sea Stallion helicopter from Kane'ohe Bay at Okinawa International University was the most recent source of anger. The crash, which injured three crew members, prompted a protest by 30,000 Okinawans in September and the demand that the nearby Futenma Air Station be closed and returned to Japanese control.

"There are a number of different discussions going on at the highest levels of our government and their government, not just on Marine presence on Okinawa, but the U.S. force presence in Japan overall," Gregson said in a meeting with reporters.

Just over a year ago Gregson assumed command of more than 74,000 Marines and sailors in the Pacific and Central Command regions.

Gregson said before there is any discussion of moving Marines, the first question should be, "What direction do we — Japan and the United States — want to take our alliance in the future and what functions and what contributions should each nation be making?"

He said the second question should be, "What is the situation we're facing in Asia?" Traditional issues remain, including concerns over the Korean Peninsula, China's rising power, and the influence of terrorism in Asia.

Gregson suggested sharing space with Japanese forces if troops are moved off Okinawa to the Japanese Mainland, but residents there have raised concern over that proposal as well.

Hawai'i is home to about 7,000 Marines. Asked if the state could sustain additional Marines, Gregson said, "Hawai'i is bigger than it looks. How many do we want to put here and why, and then we can start working on the sustainment."

He said that Bellows and Barbers Point have been utilized by the Marines in the past.

A spokesman for Gregson previously said he was not inclined to move Marines from Japan to Hawai'i, Guam or Australia.

"If you are talking about moving forces to Hawai'i, you are talking about moving them several thousand miles from Japan," said Chuck Little, a Marine Forces Pacific spokesman. "Gen. Gregson does not support the movement of large numbers of forces off Okinawa to Hawai'i because it takes them out of the geographic area that they are there to support."