Incoming US president Donald Trump has slammed what he called unfair fees for US ships passing through the Panama Canal and threatened to demand control of the waterway be returned to Washington.

He also hinted at China’s growing influence around the canal, a worrying trend for American interests as US businesses depend on the channel to move goods between the Atlantic and Pacific oceans.

The Panama Canal, which was completed by the United States in 1914, was returned to the Central American country under a 1977 deal signed by Democratic president Jimmy Carter.

He continued that if Panama could not ensure the secure, efficient and reliable operation of the channel, his administration will demand that the Panama Canal be returned in full, and without question.

However, authorities in Panama did not immediately react to Trump’s post.