President Trump suggested on Friday that the United States and China may not complete a partial trade deal this year, raising fresh doubts about prospects for a commercial truce that once was expected to be signed next weekend.

“We’ll see what happens,” the president replied when a reporter asked if the agreement would be concluded in 2019.

Speaking on the south lawn of the White House, the president added to confusion over the state of the roller coaster talks. He denied reports — which the White House had confirmed one day earlier — that he had agreed to remove some tariffs as part of an initial deal.

“I haven’t agreed to anything,” Trump told reporters. “China would like to get somewhat of a rollback, not a complete rollback because they know I won’t do it.”

The president’s remarks appeared to conflict with those of his National Economic Council director, Larry Kudlow. On Thursday, Kudlow confirmed the Chinese Commerce Ministry’s claim of a tariff accord, telling Bloomberg News: “If there’s a Phase 1 trade deal, there are going to be tariff agreements and concessions.”

But reflecting administration divisions, Peter Navarro, one of Trump’s closest trade advisers, emailed reporters a few hours after the president’s remarks to complain that media reports had been wrong.

“There is no agreement to remove any existing tariffs as a condition of signing a Phase One deal,” Navarro wrote.

Chinese officials have insisted any deal must include the immediate removal of some tariffs and a path toward the elimination of all of the levies Trump has imposed since March of last year.

The president turned to tariffs last year to force China to abandon trade practices, especially in the high-technology area, that disadvantaged American companies.

The United States currently levies tariffs on roughly $360 billion in Chinese imports and plans to extend the import fees to everything Americans buy from China starting Dec. 15.

Many administration officials opposed Trump’s decision to impose those tariffs on roughly $160 billion in products, including popular consumer goods such as smartphones and laptops. The president now is seen as willing to scrap them.

Chinese officials also want the United States to lift the 15 percent tariff Trump imposed Sept. 1 on about $112 billion in imports. In return, the administration is demanding that Beijing agree to more extensive intellectual property safeguards, according to two people familiar with the talks, who spoke on the condition of anonymity because they weren’t authorized to discuss the talks.

Trump’s whirlwind morning left unclear the state of the talks four weeks after he had announced an “agreement in principle” on an initial deal. Speaking in the Oval Office during a meeting with Chinese Vice Premier Liu He, the president on Oct. 11 called the partial deal “substantial” and said it would pave the way for additional agreements in subsequent talks.

In return for canceling a planned Oct. 15 increase in tariffs on Chinese products, Trump said he had secured Beijing’s promise to make annual purchases of $40 billion to $50 billion worth of American crops.

China also had agreed to toughen protections for intellectual property, open its financial services market to foreign companies, and foreclose depressing the value of its currency to gain a trade advantage, administration officials said.

“I don’t think it should be a problem, getting it papered,” the president said at the time, adding that he expected that to occur over the next four weeks.

Four weeks later, the talks are shrouded in uncertainty. Initial plans for Trump and Chinese President Xi Jinping to sign the “phase one” deal on the sidelines of an Asian-Pacific summit in Santiago, Chile, next weekend have been abandoned.

The president Friday repeated his claim that any signing ceremony will be held in the United States, possibly in Iowa or elsewhere in “farm country,” he said.

The latest exchange over tariffs began with a Chinese Commerce Ministry statement Thursday in Beijing.

“If the two parties reach the first-phase agreement, they should, in accordance with the contents of the agreement, simultaneously and proportionally cancel the tariffs that were already raised,” said Gao Feng, a ministry spokesman.

Robert E. Lighthizer, the U.S. trade representative, is pushing China to accept an enforcement mechanism that would condition tariff reductions on Chinese implementation of the agreement. Tariffs would fall — or rise — depending on whether Beijing complied with specific terms, said one person familiar with the talks who spoke on the condition of anonymity because the person wasn’t authorized to discuss the talks.