According to an internal message that AP has taken part of, the affected officials who are posted abroad will be laid off for 120 days before they then formally lose their jobs. For those who instead have their employment on American soil, the notice period is 60 days, according to the message.
Earlier on Friday, The Washington Post reported that the American Ministry of Foreign Affairs would start notifying staff shortly.
The administration under President Donald Trump has driven to reform American diplomacy and has worked hard to reduce the state's expenses by dismantling entire departments, such as the Department of Education.
The measure shows that the leadership "either does not appreciate its employees or simply does not care", said an anonymous employee to the newspaper last month, in light of the expected notices.
Both current and former diplomats have strongly criticized the cuts, which they believe will weaken the US's influence and ability to counter threats abroad.