The entire staff of the Serbian Embassy in the Macedonian capital has been withdrawn for urgent consultations in Belgrade in a move that has further strained relations between the Balkan neighbors.
The Macedonian Foreign Ministry said it "is not aware of the reasons for this decision."
Serbian officials have not given a reason for the withdrawal. Serbian state TV said Foreign Minister Ivica Dacic will comment on Monday.
Relations between the two countries have been strained since Macedonia's Prime Minister Zoran Zaev formed his coalition government this spring, almost six months after a parliamentary election.
Both Serbia and its ally Russia have voiced support for Macedonia's former Prime Minister Nikola Gruevski's conservative VMRO-DPMNE party. The party placed first in the election, but without winning a governing majority.