TOKYO (AFP) - US President Barack Obama on Thursday told a press conference in Japan that islands at the centre of a bitter territorial dispute with China are covered by a defence treaty that would oblige Washington to act if they were attacked.

"Article five (of the US-Japan security treaty) covers all territories under Japan's administration including (the) Senkaku islands," he said. The disputed islands are known as Diaoyu in China.

"We do not believe that they should be subject to change unilaterally, and what is a consistent part of the alliance is that the treaty covers all territories administered by Japan.

"This is not a new position. This is a consistent one."

"We stand together in calling for disputes in the region, including maritime issues, to be resolved peacefully through dialogue."