WASHINGTON—In the strongest sign yet that an accord is near, U.S. Trade Representative Robert Lighthizer said Wednesday that the U.S. was abandoning for now its threat to raise tariffs to 25% on $200 billion of Chinese goods.

His comments came following a House Ways and Means Committee meeting where Mr. Lighthizer said that the U.S. and China have reached a tentative agreement on a mechanism to enforce the trade deal, which has long been a stumbling block in talks.

In a response to a question after, Mr. Lighthizer said that his agency would drop plans to move beyond the 10% tariffs now in force. Several hours later his office filed papers to “suspend the scheduled tariff increase until further notice.” Mr. Trump had said Sunday the higher tariffs would be delayed but didn’t give a time frame.

The threat of higher tariffs had shaken world markets and forced U.S. businesses to consider moving operations out of China—while also pressuring Beijing to negotiate a cease-fire. Now, U.S. and Chinese officials suggest the two countries are poised to finish a deal over the next month following a likely summit between Mr. Trump and Chinese President Xi Jinping at Mr. Trump’s Mar-a-Lago estate in Florida.

“It does appear that over the past week of negotiations progress was made in areas of importance to the business community,” said Myron Brilliant, executive vice president of the U.S. Chamber of Commerce, which has pressed the administration to focus on Chinese industrial policies and intellectual property protection.