President-elect Donald Trump's transition team has ordered all political ambassadors appointed by Barack Obama to leave their overseas posts by Inauguration Day on 20 January.

The mandate – which was reportedly issued "without exceptions" – breaks precedent as no grace period is being provided to the ambassadors to vacate their posts. It could also leave the US without Senate-confirmed envoys for months in key countries like Britain, Canada and Germany, the New York Times (NYT) reported.

In the past, the administrations of both Democrats and Republicans have handed extensions to ambassadors, allowing them to remain in place for a few weeks or even months – especially to those with school-age children.

A senior official from the transition team told the NYT that there was no ill will regarding the move and noted that the order is intended to ensure Obama's appointees leave on schedule.

Some of the ambassadors may consider appealing against the decision to Rex Tillerson, Trump's nominee for secretary of state. The State Department has reportedly informed all ambassadors to submit their resignations effective 20 January and asked those who want an extension to formally submit their requests.

A former US ambassador to Finland, Derek Shearer said: "It feels like there's an element just of spite and payback in it. I don't see a higher policy motive."

Incoming presidents often grant ambassadors a grace period to complete their diplomatic business while their successors are in the confirmation process. Former presidents Bill Clinton, George W Bush and Barack Obama had given extensions to a few ambassadors.

Trump has already appointed two ambassadors David Friedman and Terry Branstad to Israel and China, respectively.

US ambassador to Germany
US Secretary of State John Kerry (C) presents the US ambassador to Germany John B Emerson (L) to German President Joachim Gauck at the Hotel Bayerischer Hof on the sidelines of the Munich Security Conference in Munich (File image)Brendan Smialowski/Reuters