An American delegation is expected to travel to Beijing sometime between now and Mr. Xi’s trip to Mar-a-Lago to continue to work out the remaining differences. The fact that Mr. Xi has agreed to come to Mar-a-Lago is viewed by the Chinese as a concession, as they originally hoped that such a meeting would take place on China’s Hainan island. But the location also represents a gamble by Mr. Trump, who could be faced with an awkward situation if Mr. Xi refuses to make final concessions while he is a guest at his resort.

Mr. Trump continued to tease the prospect of a potential deal with China on Sunday evening, saying “if all works well, we’re going to have some very big news over the next week or two.”

The president said tariffs on Chinese goods had helped propel the United States beyond China, saying “as long as I’m president, they’re not going to catch us.”

While some analysts said Mr. Trump’s advisers appeared likely to secure greater concessions than past administrations have achieved, others remain skeptical that United States can significantly transform the economic relationship with China.

The president’s announcement followed days of negotiations in which American and Chinese officials met in board rooms near the White House to work line-by-line through a handful of documents covering intellectual property, services and subsidies. The Chinese were ready to commit to billions of dollars of purchases of American soybeans, beef, natural gas and other products, though they have resisted more structural changes to their economy.

Mr. Trump has long criticized China for undercutting American workers, and his advisers have tried to pressure the country into making firm commitments to protect American intellectual property, give foreign companies equal access to Chinese markets and reduce subsidies to state-owned firms. But some of these goals run counter to China’s own ambitions of cementing the Communist Party’s control over the economy and the economic dominance of its state-owned firms.

One component of this week’s agreement was a pledge by China not to artificially weaken the value of its heavily managed currency, according to people with knowledge of the negotiations. A weaker currency would make Chinese products cheaper abroad and lessen the impact of American tariffs. Under the agreement reached this week, the Chinese must notify the United States when and why they are intervening in their currency. If they violate the agreement, the Trump administration would ratchet up tariffs on Chinese goods, according to one person with knowledge of the negotiations.