The United States will add an additional 100 percent tariff on imports from China and impose export controls on all critical US-made software from November, US President Donald Trump said on Friday.

"Starting November 1st, 2025 (or sooner, depending on any further actions or changes taken by China), the United States of America will impose a Tariff of 100% on China, over and above any Tariff that they are currently paying," Trump wrote on his account on Truth Social.

Trump on Friday morning threatened to impose "massive" new tariffs in a social media post.

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"One of the Policies that we are calculating at this moment is a massive increase of Tariffs on Chinese products coming into the United States of America," Trump wrote earlier. "There are many other countermeasures that are, likewise, under serious consideration. Thank you for your attention to this matter!"

Chinese and US trade teams just held a new round of talks in Madrid, Spain, in September, following discussions earlier in Switzerland, Britain and Sweden.

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US stocks tumbled to their worst single-day performance since the "tariff war" in April after Trump's announcement of reciprocal tariffs.