President Trump provided notice of the tariffs to begin on Aug. 1 by posting letters on Truth Social that were addressed to the leaders of the various countries.

In letters so far to 14 countries, including smaller exporters to the United States such as Serbia, Thailand and Tunisia, Trump hinted at opportunities for additional negotiations, even while warning that reprisals would draw a like-for-like response.

The U.S.’s closest security allies in Asia, along with six Southeast Asian countries, have been given another three weeks to negotiate trade deals — or face higher tariffs.