The State Department declined to provide a list of the diplomats being recalled. A senior department official said on Monday the move was "a standard process in any administration" but critics said that was not so.
"An ambassador is a personal representative of the president, and it is the president's right to ensure that he has individuals in these countries who advance the America First agenda," said the official, who spoke on condition of anonymity.
Nearly 30 senior diplomats were among those ordered back to Washington, people familiar with the matter said.
They were posted to smaller countries where the top US representative has traditionally been from the Foreign Service, which is made up of career officials not aligned with a political party, the people said.
The recalled diplomats were encouraged to find new roles in the State Department, a second US official said.
The American Foreign Service Association representing foreign service officers said it was working to confirm which members were recalled after some reported being notified by phone with no explanation - a process its spokesperson called "highly irregular".
"Abrupt, unexplained recalls reflect the same pattern of institutional sabotage and politicisation our survey data shows is already harming morale, effectiveness, and US credibility abroad," spokesperson Nikki Gamer said in an email.
The State Department declined to respond to Gamer's comments.
Trump has sought to place loyalists in senior roles since starting his second term after encountering resistance during his first term advancing his foreign policy priorities within the US national security establishment.
Jeanne Shaheen, ranking Democrat on the US Senate Committee on Foreign Relations, assailed the Republican administration's removal of the diplomats while about 80 ambassadorial posts remain vacant.
"President Trump is giving away US leadership to China and Russia by removing qualified career Ambassadors who serve faithfully no matter who's in power," Shaheen posted on X.
"This makes America less safe, less strong and less prosperous."
