Trump wrote in a social media post on Friday that "the United States of America will impose a Tariff of 100% on China, over and above any Tariff that they are currently paying."
He said the additional levy will take effect on November 1, but may come sooner, "depending on any further actions or changes taken by China."
He also said the US "will impose Export Controls on any and all critical software" on November 1.
In another post, Trump said he was to meet Chinese President Xi Jinping at the Asia-Pacific Economic Cooperation forum in South Korea later this month but that "now there seems to be no reason to do so."
Trump later told reporters at the White House that the new tariff is a countermeasure against China's toughening of export controls on rare earths.
He described the Chinese move as "shocking," aimed at the whole world, and "very, very bad."
As for his possible meeting with Xi, Trump said he has not canceled it and that "I'm going to be there regardless, so I would assume we might have it."
The two countries previously imposed levies exceeding 100 percent on each other after the Trump administration announced its tariffs measures this year. But both sides later lowered the rates considerably and agreed to pause 24 percent of the levies until November 10.
Observers say that if the new US tariff is implemented, the conflict between Washington and Beijing will inevitably escalate again.
