The Treasury secretary is heading to China on Monday with Robert E. Lighthizer, the Trump administration’s top trade negotiator, to try to resolve the remaining sticking points between the countries. Chinese officials are expected to come to Washington on May 8 to continue — and possibly conclude — the negotiations.

The United States and China have been locked in a trade war for months, exchanging tit-for-tat tariffs on billions of dollars’ worth of products and rattling global markets.

Mr. Trump imposed punishing tariffs on $250 billion worth of Chinese goods in an effort to force Beijing to make significant changes to its economic practices, including China’s requirement that American companies turn over valuable intellectual property as a condition of doing business there.

While Mr. Trump has said repeatedly that talks with China are going well, he has continued to insist that the United States could walk away if it does not get the trade terms it wants. Still, the president stirred optimism last week that the negotiations could be nearing an end when he said President Xi Jinping of China could soon be visiting the White House. Mr. Trump has previously said he expects to hold a signing ceremony with Mr. Xi in the United States.

Mr. Mnuchin declined to predict whether the negotiations would be wrapped up by the end of June but said he believes that both countries want to reach a deal. He also would not say if a breakdown in the talks would lead Mr. Trump to impose more tariffs.