The United States is frustrated by Japan's delay in relocating a major U.S. military base, even as the U.S. signals a willingness to be patient with Tokyo's new government.

The moderate approach reflects the Obama administration's desire not to destroy ties with its most important Asian ally at a time when China is building up its military and North Korean provocations include nuclear and missile tests.

Despite widespread displeasure that Japan has backtracked on a signed agreement, the U.S. is giving Japanese Prime Minister Yukio Hatoyama some time to get his footing in the aftermath of elections that threw out a party that had ruled Japan for most of the post-World War II era. That patience has its limits, however, as U.S. officials indicated Tuesday after Hatoyama said Japan needs several more months to decide on the relocation of the U.S. Marine Corps Air Station Futenma on the southern island of Okinawa.

The Futenma move is the centerpiece of a sweeping realignment plan for the 47,000 U.S. troops in Japan, and Hatoyama's comments that a hasty decision on moving the base would be irresponsible appear to spoil the U.S. goal of resolving the matter by the end of the year.

Gen. James Conway, the U.S. Marine Corps commandant, told reporters he had not been informed about the delay. But, he said, "at this point, it sounds like it's more and more up in the air, which is unfortunate."

"The Futenma replacement facility is absolutely vital to the defense that we provide for the entire region," Conway said.

Arizona Sen. John McCain, the top Republican on the Senate Armed Services Committee and President Barack Obama's rival in the 2008 presidential race, spoke of the need to act urgently.

"American troops in Japan are a force of stability in Asia," McCain told a Washington think tank Tuesday. "I hope we can work out these negotiations as quickly as possible, since there is questioning throughout Asia as to what exactly the U.S.-Japanese relationship will be in light of the new government of Japan."

A 2006 U.S.-Japan reorganization plan was meant to ease the load on Okinawa, which hosts more than half the U.S. troops in Japan. Residents in Okinawa complain about noise, pollution and crime _ including the 1995 rape of a 12-year-old girl by three U.S. servicemen _ and many want the Futenma airfield closed and its functions moved off the island.

Hatoyama, whose party came to power after a landslide election victory in August, has promised that Japan would adopt a less subservient relationship with the U.S. and has refused to accept any deadlines for signing off on the deal to move Futenma to a more remote part of Okinawa.