President Trump announced Thursday that his administration would impose a 10 percent tariff on the $300 billion of imports from China that have not yet been subject to new import duties.

Trump described the new tariffs as “small” and said talks would continue. The new tariffs will kick-in on September 1, according to President Trump’s tweet.

In his tweets, Trump accused China of repeated reneging or failing to live up to past agreements.

A team of U.S. officials led by Treasury Secretary Steven Mnuchin and U.S. Trade Representative Robert Lighthizer flew to China this week to resume trade negotiations. Lighthizer and Mnuchin briefed President Trump on the talks this morning, according to a White House source. The tweets indicate that the U.S. does not think the talks made sufficient progress, the source said.