When President Donald Trump revealed that his administration had struck a "massive" trade and investment deal with Japan, he described it as "completed"—but it must still pass the Japanese parliament, called the Diet, which is riven with political turmoil.

Japan's Prime Minister Shigeru Ishiba recently confirmed the deal, and the country's chief trade negotiator earlier said in a Facebook post that he had visited the White House, adding the hashtag "Mission accomplished".

By Tim Kelly, Satoshi Sugiyama and Leika Kihara TOKYO (Reuters) -Japanese Prime Minister Shigeru Ishiba plans to step down following a bruising upper house election defeat, a source told Reuters, as the embattled premier announced a long-sought trade deal with U.