A U.S. Marine CH-46E helicopter takes off from the U.S. Marine Corps Air Station Futenma in Ginowan, Okinawa prefecture, on April 26, 2010. (Toshifumi Kitamura/AFP/Getty Images)

The U.S. and Japan on Wednesday tweaked a long-stalled military realignment plan, hoping to streamline the transfer of Marines from Okinawa to Guam by cutting the number of troops to be moved and sidestepping a separate controversy about the future location of the Okinawa base.

A joint statement about the agreement provided no specifics about the new deal, but Japanese media reported that the United States is likely to send roughly 4,700 troops — not the original 8,000 — to Guam, signaling a possible scaling back of a planned $23 billion military expansion on the tiny island. The remaining 3,300 troops will be spread across the Asia-Pacific, rotated through bases in Australia and the Philippines.

But the agreement would make it easier for the U.S. to remove those troops from Okinawa in the first place. Based on the deal Tokyo and Washington reached in 2006, Marines were to move to Guam only after Japan resolved one of its thorniest domestic issues, securing new land for an existing U.S. air base that Okinawans don’t want on their island — in its current location, or anywhere else.

“We separated those two things in the package,” Japanese foreign minister Koichiro Gemba said. “The transfer of the Marines to Guam will not be related to progress in the relocation of Futenma station.”

The U.S. and Japanese central governments long ago determined that the noisy Futenma Marine base, situated in the middle of a populated city, should be reconstructed on a northern and less populated slice of land in Okinawa. But they have been unable to begin work on the project, stymied by local opposition. Okinawans say they carry an inordinate burden by hosting about half the U.S. troops in Japan.

By detaching the Guam move from the Futenma Marine base controversy, the U.S. eased concerns that both sides of the deals were about to collapse. Gemba said he did not yet know a target date for the Marine transfer to Guam.

Last year several U.S. senators recommended reducing the Pentagon’s planned military build-up in Guam — a build-up that could cost as much as $23 billion, according to government estimates. The Pentagon is trying to slash about $490 billion in spending over the next decade.

But the Futenma relocation remains unresolved, with no clear alternative to the status quo, experts in Tokyo say.

Futenma sits in the middle of Ginowan City, surrounded by schools and houses. In 2004, a Marine helicopter crashed into a nearby college campus; nobody died, but the incident inflamed an opposition that had already existed for almost a decade, dating back to the 1995 rape of an Okinawa 12-year-old by three U.S. servicemen.

In the agreement announced Wednesday, the United States and Japan reaffirmed their hope to relocate the Futenma base to the less-populated coastal area known as Henoko Bay. But so far, a series of Japanese prime ministers — each of whom survived only a short time in office — have been unable to gather support for that plan among Okinawa’s people and politicians.

“Okinawa’s opposition is still quite strong and still unified,” said Manabu Sato, a professor of political science at Okinawa International University. “Probably the obstacles are even greater than what the Japanese government in Tokyo expected. They have been trying to persuade the governor here to change his position by dropping a large amount of money and offering aid. But still the government maintains stiff opposition.”

The Yomiuri Shimbun, Japan’s largest newspaper, said in an editorial that the changes to the 2006 plan make sense. But it also outlined a fear: Without great incentive to find a solution for Futenma’s relocation, the U.S. and Japan will stick with the status quo.

“This would mean the dangerous situation ... would become permanent,” the editorial said.