WASHINGTON — President Trump on Tuesday unexpectedly put off new tariffs on many Chinese goods, including cellphones, laptop computers and toys, until after the start of the Christmas shopping season, acknowledging the effect that his protracted trade war with Beijing could have on Americans.

Mr. Trump pushed a 10 percent tariff on some imports to Dec. 15, and excluded others from it entirely, while facing mounting pressure from businesses and consumer groups over the harm they say the trade conflict is doing.

The stock market soared after the announcement, following weeks of volatility driven by fears that the standoff between the world’s two largest economies could hamper global economic growth.

The decision was the latest twist in a dispute during which China and the United States have alternately escalated tensions with tit-for-tat tariffs and softened their positions as they sought a deal.