President Donald Trump cast doubts on Wednesday regarding the prospects for talks between the U.S. and China that are aimed at heading off a trade war. An Associated Press report says just four days after the two countries suspended their plans to impose up to $200 billion in tariffs on each other, Trump declared in a tweet that a more detailed agreement “will be too hard to get done.” While he says the talks are moving along nicely, Trump added that the negotiations would require a different structure and would need to allow the U.S. to verify results after completion. It’s not immediately clear what kind of structure the president has in mind. Talks in Washington, D.C., last week resulted in an agreement in which Beijing said it would “substantially reduce” America’s trade deficit with China. However, China didn’t commit to any specific amount of reduction. It also didn’t address the big issues between Washington and Beijing, which is the method China uses to try to overtake the U.S. technological supremacy, which is to demand that U.S. companies hand over some of their technology in exchange for access to the Chinese market.