John Feeley announced his resignation in a letter to the State Department.
"As a junior foreign service officer, I signed an oath to serve faithfully the president and his administration in an apolitical fashion, even when I might not agree with certain policies. My instructors made clear that if I believed I could not do that, I would be honour bound to resign. That time has come", according to an excerpt of the letter obtained by Reuters.
However, the State Department, in a statement, said that Feeley retired for "personal reasons, as of 9 March this year".
A Panama Paper reported about Feeley's resignation before the Trump's racist remark on the immigrants from Haiti, El Salvador, and African countries.
Feeley was appointed to the diplomatic post by former US President Barack Obama in July 2015. (ANI)