President Donald Trump said he’ll keep tariffs on China until he’s sure Beijing is complying with any trade deal, refuting expectations that the two nations will agree to roll back duties as part of a lasting truce to their trade war.

“We’re not talking about removing them, we’re talking about leaving them for a substantial period of time, because we have to make sure that if we do the deal with China that China lives by the deal,” Trump told reporters at the White House on Wednesday before leaving for Ohio. “They’ve had a lot of problems living by certain deals.”

The president’s comments dim hopes that round-the-clock trade negotiations between the world’s two biggest economies could lead to them removing the roughly $360 billion in tariffs they’ve imposed on each other’s imports. Beijing has pushed the Trump administration to remove tariffs as part of any deal.

U.S. officials are concerned that Beijing is pushing back against some American demands in trade talks, people familiar with the matter said. Chinese officials have shifted their stance because after agreeing to changes to their intellectual-property policies, they haven’t received assurances from the Trump administration that tariffs imposed on their exports would be lifted, the people said.

Despite his comments on the tariffs, Trump said “the deal is coming along nicely,” adding that top U.S. negotiators will be in China this weekend working on an agreement.

One of the remaining sticking points in talks is whether the tariffs would be lifted immediately or over a period of time to allow the U.S. to monitor whether China is meeting its obligations, Bloomberg News reported earlier this month. The U.S. wants to continue to wield the threat of tariffs as leverage to ensure China won’t renege on the deal, and only lift the duties fully when Beijing implemented all parts of the agreement.