“South Korea’s Legislature is not living up to its Deal with the United States,” Trump wrote on social media.

“Because the Korean Legislature hasn’t enacted our Historic Trade Agreement, which is their prerogative, I am hereby increasing South Korean TARIFFS on Autos, Lumber, Pharma, and all other Reciprocal TARIFFS, from 15% to 25%.”

South Korea’s presidential Blue House did not have an immediate comment.

South Korea had been working to implement a deal announced with Washington in November that was going to lower US tariffs against its exports. More recently, South Korea has engaged with Washington to explain Seoul’s probe of US-based e-commerce company Coupang, stemming from a mass data leak.

Trump has used the leverage of tariffs throughout his second term in office in his foreign policy. Economists have raised concerns about the approach and the policy also faces a test in an ongoing case at the US Supreme Court.