Ambassadors in some of the most desirable foreign capitals such as London and Paris have been told they must end their service on Jan. 20 with “no exceptions,” State Department officials confirmed Thursday.

The unusually stern and specific directive to “political” ambassadors — often presidential donors and friends — came at the behest of the incoming Trump administration, two officials said. It appears to forbid any extensions for family circumstances such as allowing children to finish the school year, a customary allowance in past administrations.

The Obama administration directed what it calls non-career ambassadors to submit their resignations effective with the close of the Obama presidency Jan. 20, and ambassadors have complied, three officials said. Such orders are standard procedure. But the Dec. 23 directive first reported by the New York Times contained the additional admonition that the resignations would be blanket and final.

During previous transitions, a small number of political ambassadors would either ask or be asked to stay on briefly, after submitting their pro forma resignations, for personal or professional reasons.

Trump transition officials did not immediately respond to requests for comment on the order or whether it was intended to break with precedent.

The order would apply to high-profile Obama envoys such as Jane Hartley, a Democratic fundraiser who has served as ambassador to France, as well as to Daniel Shapiro, a former Democratic congressional aide and Obama adviser who became ambassador to Israel in 2011. Trump has named his choice to succeed Shapiro — New York bankruptcy lawyer and Trump adviser David Friedman.

Ambassadorial posts are filled from within the State Department ranks of career Foreign Service officers or from outside government. Career diplomats remain in their posts across administrations.

Since it typically takes months to select and confirm ambassadors from outside the State Department, the top spots in key foreign capitals in Europe, Asia and the Mideast could be empty this spring. Career State Department officials stand in when there is no ambassador.

Karen DeYoung contributed to this report.