The State Department instructed United States embassies around the world to start planning for staff reductions on Wednesday, sources told ABC News.

Senior embassy officials were asked to provide comprehensive lists of all employees and their employment status as part of the process, sources said, explaining that the request includes tenured, untenured and temporary duty assignments.

Embassies will be required to cut both American staff and employees hired from the location in which the embassy is based, sources added.

The State Department communication went out shortly before President Donald Trump signed an executive order on Wednesday afternoon that compelled State Department staff to comply with his administration’s foreign policy goals — while making it easier to discipline them if they don’t.

Titled “ONE VOICE FOR AMERICA’S FOREIGN RELATIONS,” the order said that the secretary of state “must maintain an exceptional workforce of patriots” in order to effectively uphold foreign policy initiatives.

That involves the ability to “reform the Foreign Service” through not only staffing revisions but also changes to collateral. It specifies revamping the set of policies and procedures that control almost every element of the State Department’s work and U.S. diplomatic presence abroad: the Foreign Affairs Manual and the Foreign Affairs Handbooks.

The full scope of the executive order’s implications will depend on the steps taken after its signing, but it could pave the way for a massive restructuring of the State Department that consolidates power under political appointees that are hand-selected by the president.

Such changes could empower the State Department to strip benefits from members of the foreign service stationed abroad, like security protections and annual paid travel to visit family members. They could impact virtually every element of the federal employees’ day-to-day jobs, from the handling of classified information to dealing with conflicts of interest.

Taken to the extreme, the order could also pave the way for shrinking the U.S. diplomatic footprint abroad — prompting the State Department to rethink the presence of U.S. embassies in certain countries altogether.

The department might reconsider membership in some international organizations or withdraw from existing diplomatic agreements.

The Trump administration is likely to face legal challenges over the order, but the law that codifies the administration of the foreign service is fairly deferential to the secretary of state.

In the past two weeks, an overwhelming majority of U.S. Agency for International Development employees who were embedded in embassies have already been put on administrative leave.

This has led a number of ambassadors and chiefs of mission to register complaints with department leadership, saying they don’t have the staff needed to oversee the USAID programs that are still in operation, according to communications reviewed by ABC News.

The Trump administration has also already fired contractors who worked on key embassy functions, including diplomatic security, and it is considering further reductions that could include untenured Diplomatic Security Service direct hires, sources said.