The meeting, to be attended by the Japanese foreign and defense ministers, U.S. Ambassador to Japan John Roos, and a senior U.S. Defense Department official, is intended to accelerate adjustments between Tokyo and Washington and also within the Japanese government, which has yet to present a clear position on the issue.

Roos will represent U.S. Secretary of State Hillary Clinton and U.S. Defense Secretary Robert Gates.

Participants will study the process of how the two countries reached the 2006 accord to relocate the U.S. Marines Corps' Futemma Air Station from a downtown residential area of Ginowan to the less densely populated city of Nago in northern Okinawa by 2014.

The accord is part of a broader Japan-U.S. agreement on the realignment of U.S. forces in Japan and involves the transfer of around 8,000 Marines from Okinawa to Guam. It was agreed under a previous government led by the Liberal Democratic Party, which is now an opposition party.

But the working group is off to rocky start, with Japanese Prime Minister Yukio Hatoyama saying Japan will engage in talks without seeing the 2006 accord as a premise and U.S. President Barack Obama saying the group will focus on the implementation of the agreement.

Differences among Japanese Cabinet members are compounding the issue, with Defense Minister Toshimi Kitazawa backing the existing deal but Foreign Minister Katsuya Okada floating the idea of transferring the air station to the nearby U.S. Kadena Air Base.

Kitazawa said in the morning that the participants will engage in a "frank exchange of opinion without setting any premise."

Japan and the United States agreed a week ago to set up the ministerial-level working group, just days before Obama visited Japan for the first time since becoming president.

Hatoyama and Obama agreed Friday in talks in Tokyo to seek an early settlement of the issue, but this was interpreted as sidestepping a potential flashpoint that could undermine the countries' security alliance.