President-elect Donald Trump threatened on Saturday that the U.S. would reassume control of the Panama Canal if it felt that Panama wasn’t honoring the terms of a 1977 treaty regarding the waterway’s legal status.

In two lengthy Truth Social posts Saturday evening, Trump accused Panama of charging U.S. vessels exorbitant rates to pass through the critical waterway. He also claimed that the treaties enabling Panama to take control of the canal in the first place also allow for the U.S. to take it back.

It is unclear what spurred Trump’s invective about the canal. While China has increased its presence in Latin America over the last two decades — and a Hong Kong-based company administers the two ports on each end of the canal — no Chinese commercial or government entity actually has any direct role in managing the flow of vessels through the critical waterway.