Japan is resisting increasing U.S. pressure to link trade with currency issues as leaders of the two close allies are set to hold a summit in Washington on Friday, with trade and North Korea high on the agenda.

Japanese ministers discussed trade and currency issues with their U.S. counterparts in Washington ahead of the summit between Prime Minister Shinzo Abe and President Donald Trump.

Trump has made clear he is unhappy with Japan's trade surplus with the United States - much of it from auto exports - and wants a two-way deal to fix it.

U.S. Treasury Secretary Steven Mnuchin had said that in future trade deals, including one with Japan, the US would like to include a provision to deter forex manipulation.

Japan has resisted the idea, out of fear that it could tie its hands in monetary policy and any future attempts to keep an unwelcome yen spike in check.

Currencies are a touchy issue for Japan because it has been criticized for keeping the yen low with massive monetary easing.