Obama expresses regret to Japan's Abe

US President Barack Obama yesterday apologised to Tokyo after WikiLeaks claimed Washington had spied on Japanese politicians, a government spokesman said.

Obama held a telephone conversation with Prime Minister Shinzo Abe yesterday morning, spokesman Yoshihide Suga said, adding that the pair agreed to work together on global economic issues in the wake of a stock market meltdown sparked by fears over China.

"President Obama said he was very sorry... as the case caused a big debate in Japan," Suga told a regular news conference, without confirming the spying claims.

He added that Abe reiterated his "serious concern" over the case.

"Prime Minister Abe told (Obama) that, if the Japanese people concerned were subject to these activities, it would risk jeopardising trusting relations between allies," Suga said.

In an earlier conversation with US Vice President Joe Biden, Abe voiced similar concerns if the spying claims were confirmed.

Last month, WikiLeaks said it had intercepts revealing years-long espionage by the US National Security Agency on Japanese officials and major companies.

Tokyo's response has been widely seen as muted compared to the anger expressed in France and Germany following similar allegations.

"(Abe and Obama) will firmly work together on the economy issue," Suga said, without elaborating.

He added that Obama repeated Washington's support for Abe's speech on the eve of the 70th anniversary of the end of WWII in which he expressed regret but also said future generations need not apologise for Japan's war record.