Navy use of the canal is infrequent, with about 40 vessels transiting annually, excluding the service’s aircraft carriers, which are too large. Allowing free access would reportedly save the U.S. about $13 million each year, according to the WSJ report.

Panama's president says the State Department's claim of an agreement granting U.S. warships free canal passage was "based on a falsity. And that's intolerable."

The Panama Canal Authority said there had been no changes made to the fees it imposes on vessels sailing through the canal, despite a statement by the US State Department, which said a deal struck with Panama would save it millions of dollars a year.