The United States will move 8,000 troops from Okinawa, southern Japan, to its territory of Guam by 2014, under an agreement signed by US Secretary of State Hillary Clinton in Tokyo on Tuesday.

Japan will contribute more than $US6 billion ($A9.24 billion) towards the planned relocation of the US Marines, first agreed between Washington and Tokyo in May 2006.

Clinton and Japan's Foreign Minister Hirofumi Nakasone signed the agreement, in which Japan pledges to pay up to $US2.8 billion in cash and $US3.29 billion in loans and other investments for the relocation cost.

Okinawans have long been reluctant hosts for more than half of the 40,000 US troops based in Japan.

The pullout aims to reduce the burden of the post-World War II American military presence in Okinawa, where residents have long complained of noise from military operations and occasional crimes by US servicemen.