The administrator of the Panama Canal has responded to criticisms from U.S. President-elect Donald Trump, denying that there is any interference from China in the canal’s operations and saying giving special privileges to any nation would only cause problems.

Treaties ratified by the Senate in 1978 established permanent neutrality, but some Republicans regret that decision.

Donald Trump has refused to rule out using military force to retake the Panama Canal that was returned by the US to Panama decades ago.

President-elect Donald J. Trump refused on Tuesday to rule out the use of military or economic coercion to force Panama to give up control of the canal that America built more than a century ago and to push Denmark to sell Greenland to the United States.

The canal was turned over to Panama on Dec. 31, 1999. For Carter, the deal signified a new beginning of mutual respect and cooperation between the U.S. and Latin America, as he said in his speech in 1978. It also showed “the last remnant of alleged American colonialism is being removed” during a time when the world moved away from imperialism.

Control of the Panama Canal, once a key U.S. presidential campaign issue for Ronald Reagan and an animating topic for people ranging from film legend John Wayne to an unpredictable Canadian-born U.S.