BUENOS AIRES, Argentina—U.S. President Donald Trump and Chinese President Xi Jinping agreed last Saturday to keep their trade war from escalating with a promise to halt the imposition of new tariffs for 90 days as the world’s two largest economies negotiate a lasting agreement. The truce emerged on the sidelines of the Group of 20 summit here.

The leaders agreed to pause the introduction of new tariffs and intensify their trade talks, Chinese Foreign Minister Wang Yi told reporters hours later. The White House called the meeting “highly successful,” saying the U.S. will leave existing tariffs on $200 billion of Chinese goods at 10 percent and refrain from raising that rate to 25 percent as planned on Jan. 1. In exchange, the U.S. wants an immediate start to talks on Trump’s biggest complaints about Chinese trade practices: intellectual property theft, non-tariff barriers and forced technology transfer.

After 90 days, if there’s no progress on structural reform, the U.S. will raise those tariffs to 25 percent, White House Press Secretary Sarah Huckabee Sanders said in a statement. China also agreed to boost its purchases of agricultural and industrial goods to reduce its trade imbalance with the U.S., she said.

“It’s an incredible deal. If it happens, it goes down as one of the largest deals ever made,” Trump told reporters aboard Air Force One as he returned from Argentina. “China right now has major trade barriers--they’re major tariffs--and also major non-tariff barriers, which are brutal. China will be getting rid of many of them.”