According to the New York Times, the Trump administration has ordered nearly thirty ambassadors to leave their posts. The American Foreign Service Association (AFSA) reported that such a mass recall has never happened before in the modern Foreign Service.
Politico also reported on the recalls.
While it is normal for new presidents to replace political appointees serving as ambassadors, career diplomats are typically allowed to continue serving because it is understood that, by virtue of being in the Foreign Service, they will carry out the wishes of whoever is in the White House regardless of political party.
But the Trump administration has had little trust in the career ranks at the State Department. Its officials have called the State Department a bastion of liberalism, and the administration has already pushed out thousands of department employees.