As ties between the US and Japan have been strained over a 2006 military agreement, Washington is stepping up efforts to persuade Tokyo to accept the deal.

US Assistant Secretary of State for East Asia and Pacific Affairs Kurt Campbell met Japan's Foreign Minister Katsuya Okada in Tokyo on Thursday.

On Wednesday, Okada cancelled a trip to Washington for talks with Secretary of State Hillary Clinton, citing his busy schedule.

In the Thursday meeting, Campbell did not mention a row over the military agreement.

He just appreciated Tokyo's preparations for US President Barack Obama's visit next week.

Campbell, who did not take questions from reporters, said Washington was 'excited about this next phase in our relationship'.

Washington has about 47,000 troops based in Japan, more than half of them on the southern island of Okinawa, where their presence has often rankled local residents.

In 2008, US Marine Tyrone Hadnott was arrested over the alleged rape of a teenage girl on the island. The news, reminiscent of a similar case in 1995, jolted the US-Japan alliance.

Japan's new government has promised to review a 2006 pact on the US troop presence, with the flashpoint being the Marine Corps Futenma Air Base located in an urban area of Okinawa.

Under the accord, the base is due to be shifted to a less-populated coastal area of Okinawa by 2014, but the new government has said the base may have to be moved off the island or even out of Japan.

AGB/AKM