U.S. President-elect Donald Trump said Saturday that the Panama Canal is charging "exorbitant prices and rates of passage” on U.S. naval and merchant ships, and he demanded that fees be lowered or else Panama should return the canal to the United States.

"The fees being charged by Panama are ridiculous, especially knowing the extraordinary generosity that has been bestowed to Panama by the U.S.,” Trump said in a post on his Truth Social platform. "This complete ‘rip-off’ of our Country will immediately stop.”

The U.S. is the canal’s biggest customer, responsible for about three quarters of the cargo transiting through each year. A prolonged drought, however, has hampered the the canal’s ability to move ships between the Atlantic and Pacific oceans. National Economic Council Director Lael Brainard said recently that the resulting disruptions contributed to the supply-chain pressures that have boosted inflation.