US President Donald Trump said Sunday the U.S. and Japan have agreed in principle on a new trade deal that calls for the Japanese to buy U.S. surplus corn. "We've been working on a deal with Japan for a long time, and we've agreed in principle," Trump said during the G-7 summit in southwest France. Details of the agreement, announced a few hours after a meeting between Trump and Japanese Prime Minister Shinzo Abe, were not immediately available. But U.S. Trade Representative Robert Lighthizer said the deal will open up markets to $7 billion in other products. Trump said the deal would likely be signed at the United Nations General Assembly meeting in September.