During Monday’s inauguration, Donald Trump repeated his threat to retake the Panama Canal. The United States controlled the waterway since the early 20th century, but in 1977 President Jimmy Carter signed a landmark treaty to give Panama control of the canal.

In recent weeks, when he was President-elect Donald Trump publicly said that Panama should return the Panama Canal to the United States, and he would not rule out using military force to reclaim it. At his presidential Inauguration on Monday Trump doubled down on saying that his new administration was going to take back the canal.

U.S. President Donald Trump’s insistence that he wants to have the Panama Canal back under U.S. control is feeding nationalist sentiment and worry in Panama, home to the critical trade route and a country familiar with U.