Dec. 23 (UPI) -- The White House sent home as many as 30 career diplomats and other overseas officials as part of an effort to ensure the U.S. Foreign Service toes the line on President Donald Trump's "America First" policy.

The ambassadors and chiefs of mission in Asia, Africa, Latin America and Europe were notified by phone beginning last week that they were being recalled to the United States and must vacate their posts by the middle of January, unnamed officials told The New York Times, The Washington Post and CNN.

The departure of so many U.S. envoys would create a sizeable hole in America's representation internationally at a time when Trump is looking to diplomatic efforts to provide U.S. solutions to disputes around the world.

The Times said all those recalled were appointed and confirmed by the U.S. Senate under the previous administration of President Joe Biden, but the Post reported that no less than 24 of the career diplomats had served under both Democratic and Republican administrations.

All of the ambassadors affected received their latest promotion under Biden.