The State Department has informed the media that John Feeley, the USA ambassador to Panama, plans to leave his position in March.
"My instructors made clear that if I believed I could not do that, I would be honor bound to resign", Feeley continued. "That time has come", Feeley wrote.
Feeley first joined the State Department in 1990, and is a Latin America specialist.
It was not a direct response to Mr Trump'salleged use of the term "shithole" to describe Haiti and African countries. He notified the White House of his planned departure, as well as Panama's president.
Various press reports in Panama said Feeleys decision to leave the post was made before reports of Trumps offensive remarks.
But an excerpt from his resignation letter reported by Reuters indicates that Feeley is indeed resigning out of protest of the Trump presidency. He tweeted: "Never said anything derogatory about Haitians other than Haiti is, obviously, a very poor and troubled country". Made up by Dems. "Probably should record future meetings - unfortunately, no trust!"