U.S. Secretary of State Hillary Clinton left Washington for Hawaii Monday, starting her 10-day tour to the Pacific region, during which she is to meet with her Japanese counterpart Katsuya Okada Tuesday, as a row surrounding a U.S. military base in Okinawa strains relations between the two countries.

Clinton herself sought to downplay the impact of the base issue on relations, saying Monday the alliance is "much bigger than any one particular issue."

However, the U.S. Marine's Futenma base in Okinawa seems to dominate the back and forth between the two countries recently.

Last week, Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell asked for "a very clear set of statements on the part of the Japanese government on its desire t ocontinue to work closely with us," saying the two sides should move beyond their row surrounding Futenma.

Clinton used much softer language. She said during a fuel stop in California en route to Hawaii, where her trip would begin, that her meeting with Okada was to "reaffirm the centrality of our 50-year-old alliance."

According to a Status of Forces Agreement (SOFA) signed by Japan's former governing Liberal Democratic Party (LDP) and U.S. administration of former President George W. Bush in 2006, 8,000 U.S. troops will be relocated from Okinawa Prefecture to Guam, and abase in the urban center of Futenma will be moved to a more rural area, part of a broader realignment of U.S. troops in Japan. Japan hosts some 47,000 U.S. military personnel, about half of which are stationed in Okinawa.

Since coming to power last year, the Democratic Party of Japan (DPJ) has pushed to see negotiations restart on the SOFA agreement, creating tension between the two countries. Prime Minister Yukio Hatoyama has pledged to decide by May how to proceed on the base issue.

Apart from talks with Okada, Clinton will deliver a policy speech focused on Asia-Pacific multilateral engagement in Hawaii, and will be consulting with the Pacific Command.

She will be traveling to Papua New Guinea, New Zealand and Australia from Jan. 14 to Jan. 19, her first visit to the region since becoming the secretary of state.

In Canberra, Clinton, U.S. Secretary of Defense Robert Gates and their Australian counterparts Stephen Smith and John Falkner will participate in the 25th Australia-U.S. Ministerial Consultations to discuss key global and regional security challenges.