Some 8,000 US troops will be moved from the Japanese island of Okinawa, with other bases earmarked for closure. Japan's military will take a greater role in maintaining security in the Asia-Pacific region and will receive US anti-ballistic missile technology.

The US at present has more than 40,000 troops in Japan, half in Okinawa, where residents have long campaigned for a reduction, complaining of crime, accidents and excessive noise.

Eight thousand of the troops on Okinawa will be relocated to the Pacific island of Guam, a US territory, by 2014.

The US airfield at Futenma, Okinawa, will also be closed by 2014, replaced by two new runways on a less congested part of the island.

Under the deal, US Patriot missiles will be deployed to Japan as soon as possible.

It was finalised at a meeting in Washington between US Defence Secretary Donald Rumsfeld, Secretary of State Condoleezza Rice and Japan's Foreign Minister Taro Aso and the head of Japan's defence agency Fukushiro Nukaga.

They called the US-Japan relationship "the indispensable foundation of Japan's security and of peace and stability in the Asia-Pacific region and the linchpin of American security policy in the region".

The full cost of the restructuring has not been finalised but is believed to be tens of billions of dollars.