TOKYO — Thousands of people rallied on a remote Japanese island Sunday, protesting against a possible government move to relocate a major US air base there.

The issue centres around a decision by Prime Minister Yukio Hatoyama to review a 2006 agreement with the United States to allow the Futenma Marine Corps Air Station to be moved from an urban area to a quieter coastal part of Okinawa.

But media have since reported that the government is planning to transfer the base to Tokunoshima, a sub-tropical island in Kagoshima prefecture, 200 kilometres (125 miles) north of Okinawa.

Hatoyama's apparent indecision on the issue has become a thorn in Japan-US relations while he battles a slide in his popularity at home.

"Let us spread this protest movement to the end," Hideki Takaoka, mayor of a town on Tokunoshima, told the rally, according to television footage.

"Down with the US base," the protesters chanted at the rally on Tokunoshima, which has 27,000 islanders." The sugar cane industry and dairy farming are major contributors to the island's economy.

"We prepared 13,000 flyers and all of them were gone," island official Osamu Minobe told AFP by telephone. Organisers estimated that 15,000 people turned out but police said they did not count the numbers.

"I believe we can change the government's attitude by sending our message today," another town mayor, Akira Okubo, told Japanese media.

Premier Hatoyama has told US President Barack Obama he will find a solution by the end of May.

The Okinawa chain, strategically located close to China and the Korean peninsula, hosts more than half of 47,000 US troops based in Japan.

The 1995 rape of a Okinawa school girl by three US servicemen prompted mass protests that led to the relocation plan, coupled with the transfer of 8,000 marines to the US Pacific territory of Guam.

But Hatoyama has yet to present a definite alternative plan while the Obama administration has repeatedly said the 2006 agreement is the best option.

Japanese media have speculated Hatoyama might have to resign if he fails to resolve the row before this self-imposed deadline expires.

Tokunoshima hosted a former Japanese military air base during World War II and was returned to Japanese rule in 1953 after US military occupation.