Postman Ceclio Mustelier organises letters at a post office in Havana, Cuba, June 1, 2018. REUTERS/Fernando Medina

HAVANA (Reuters) - Cuba and the United States are making the re-establishment of postal services permanent after a trial run, the state-run Cuban News Agency reported on Friday, as cooperation in some areas inches forward despite a chill in relations under the Trump administration.

The former Cold War foes first restored direct mail service as a pilot program in December 2015 as part of the policy of detente pursued by former U.S. President Barack Obama with then Cuban President Raul Castro.

Since taking office in January last year, President Donald Trump has struck a more hostile tone towards the Communist-run island and has rolled back parts of the normalization of relations, making trade and travel more difficult once more.

But Trump has left in place key Obama-era changes such as restored diplomatic relations, regular flights from the United States and cruise ship visits. Bilateral talks continue on cooperation in areas of mutual interest such as security.

“The re-establishment of this service allows to send post in direct flights between Cuba and the United States,” the Cuban Post Office said in a statement.

Direct mail service between the United States and Cuba was suspended since 1963. Despite the ban, letters and other mail still flowed between the United States and the island nation 90 miles (145 km) away through other countries such as Canada, Mexico and Panama.