The Trump administration is recalling dozens of career diplomats from overseas posts in the next month, according to a source familiar with the matter, the latest shakeup at the U.S. State Department. 

More than two dozen senior diplomats have received notice that they must leave their roles in the next month, according to the source. 

According to the American Foreign Service Association, the labor union that represents the U.S. foreign service and career diplomats, those affected by the recall report being notified by a phone call that they were being removed from their posts “abruptly,” with no explanation provided.

They were directed to vacate their posts by Jan. 15 or 16.

“This method is highly irregular,” a spokesperson for AFSA told ABC News. 

“This is not normal practice. Career diplomats and ambassadors are not typically recalled in this manner. The lack of transparency and process breaks sharply with longstanding norms,” the spokesperson said. 

Most of the impacted ambassadors are serving at U.S. diplomatic posts in Africa, but the removals also affect posts in Europe, Asia, the Middle East, and the Western Hemisphere. 

A senior State Department official described the recall of the ambassadors as “a standard process in any administration.”

“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,” they said.

The State Department declined to comment on specific numbers or ambassadors affected.

AFSA confirmed there is no official, verified list of recalled ambassadors.

There are various lists circulating that appear to be crowdsourced from people inside and outside the department, according AFSA.

POLITICO first reported on the removal of the diplomats.

The recall is the latest move by the Trump administration to reshape the State Department to align it more with its “America First” priorities. The recall comes after more than 1,300 officials and more than 240 foreign service officers were laid off earlier this year as part of what the administration said was a major reorganization aimed at increasing efficiency and reducing government size. 

It is typically normal for new presidents to replace political appointments service in ambassador roles; however, career diplomats are typically allowed to continue serving in their roles. 

The AFSA slammed the recall, saying it sends a “chilling signal” to career foreign service officers that their oaths to the Constitution take a backseat to political loyalty. 

“Removing senior diplomats without cause undermines U.S. credibility abroad and sends a chilling signal to the professional Foreign Service: experience and an oath to the Constitution take a backseat to political loyalty. This is not how America leads,” the statement said.

AFSA says the recall represents “a steady erosion of norms, transparency, and professional independence in the Foreign Service.”

“Abrupt, unexplained recalls reflect the same pattern of institutional sabotage and politicization our survey data shows is already harming morale, effectiveness, and U.S. credibility abroad,” the spokesperson said.

AFSA is working with partners to confirm names one-by-one through direct contacts.

ABC News’ Luis Martinez and Josh Margolin contributed to this report.