Those who remain will, together with local aid workers, unclear how many, manage the few "life-saving" programs and projects that the Trump administration has allowed to continue for the time being.
President Donald Trump and his "efficiency chief" Elon Musk have already frozen the funding to the agency and shut down aid programs around the world, while employees have been laid off.
On Thursday, unions for government employees filed lawsuits demanding that the shutdown be stopped.
It is unclear whether more services than the 300 currently mentioned will remain. It will become clearer when the Trump administration has completed its review of the aid programs. Those who are allowed to remain will be placed under the Foreign Ministry, according to the government.
It will be foreign aid that is sensible and in line with our national interest, said Foreign Minister Marco Rubio on Thursday.
USAID has had offices in around 60 countries and operations in around 120 countries and is considered the world's largest single donor of aid.
