China’s top trade negotiator is heading to Washington for two days of trade talks, despite President Trump’s threat to impose new tariffs on hundreds of billions of dollars’ worth of Chinese goods.

China’s Commerce Ministry announced on Tuesday that Vice Premier Liu He, one of the country’s leading economic policymakers, would join a delegation of Chinese officials who will hold further trade talks on Thursday and Friday with the Trump administration. Mr. Liu is a close adviser and confidant of President Xi Jinping, China’s top leader, and his participation could improve the chances of striking a deal.

Still, the atmosphere surrounding the trade talks has shifted dramatically since a week ago, when this week’s discussions were seen as a possible last round before the two sides halted a trade war that has made world markets shudder and thrown a damper on the global economic outlook.

Mr. Liu’s participation was thrown in doubt after Mr. Trump announced in two tweets on Sunday that he would raise American tariffs on Friday to 25 percent from 10 percent for $200 billion a year in Chinese goods. The Trump administration cited what it called backpedaling by Chinese officials during talks held last week in Beijing.