“US government vessels can now transit the Panama Canal without charge fees, saving the US government millions of dollars a year,” the state department said in a post on social media platform X.

It was the first public announcement of promises hinted at by US secretary of state Marco Rubio, who said that Panama offered concessions during his talks on Sunday.

Rubio said he had told Panama that it was unfair for the US to be in a position to defend the vital waterway and also to be charged for its use.

Since winning the November US election, Trump has refused to rule out the use of force to seize the canal, through which 40% of US container traffic passes.

Trump and Rubio have complained about Chinese investment – including ports on both sides of the canal – and warned that Beijing could close the waterway to the US in a crisis.

Panama has forcefully denied Trump’s repeated allegations that China has been given a role in operating the canal.

However, it has also moved to address US concerns. After his talks with Rubio, President Jose Raul Mulino said that Panama would not renew membership in the belt and road initiative, Beijing’s signature infrastructure-building programme.

Rubio told reporters on Monday that his talks with Mulino were “respectful” and that the visit was “going to achieve potentially good things that assuage concerns we have”.

Trump, however, said that he was still “not happy,” although he acknowledged that Panama had “agreed to certain things”.

The US and Panama are scheduled to hold new talks on Friday to discuss the canal.

Trump in his inaugural address said the US would be “taking back” the canal – built more than a century ago by Washington with Afro-Caribbean labour and handed back to Panama at the end of 1999.