Obama kicks off Asia tour in Japan

US President Barack Obama yesterday assured Japan that islands at the centre of its territorial dispute with China are covered by a bilateral defence treaty.
In an interview ahead of his Asian tour, Obama said the US would oppose any attempt to undermine Japan's control over the islands. US officials have made such comments in the past, but this is the first time Obama has given such explicit support.
He arrived in Japan yesterday ahead of stops in three other Asian nations; South Korea, Malaysia and Philippine. Obama's trip - from 23-29 April - comes nearly seven months after he cancelled a visit to the region due to a government shutdown.
China's foreign ministry has said it opposes the islands being covered by the defence treaty. Obama is not going to Beijing, but relations with China are expected to dominate his meetings with regional leaders.
The trip was an opportunity to reinforce the importance the US placed on Asia, former US Assistant Secretary of State PJ Crowley told the BBC.
"Many traditional allies... [also] value a strong US presence in the region to balance against an assertive China," he said.
The visit comes amid a "period of very significant tension among American allies, and between American allies and China", he added.
China-Japan relations are severely strained over a raft of issues, including East China Sea islands - called Senkaku in Japan and Diaoyu in China - that both claim.
Japan controls the islands but Chinese ships have sailed repeatedly in and out of what Japan says are its territorial waters as Beijing presses its claim. Last year, China declared an air defence identification zone over the islands, drawing widespread criticism.
Japan depends on the US for its security, under a decades-old alliance that dates back to the end of World War Two.
The US, however, is keen for Japan to take on greater responsibility for its own security - an area where Obama and Abe are likely to be in general agreement.
Obama is also expected to have to balance bolstering US ties with each Asian ally with improving communication among them, particularly between South Korea and Japan.
The two Asian nations are at odds over a separate set of disputed islands, as well as historical issues linked to Japan's war history.