Under Article 9 of the Vienna Convention on Diplomatic Relations, a receiving state may "at any time and without having to explain its decision" declare any member of a diplomatic staff persona non grata.
根據《維也納外交關係公約》第9條，任何國家可以“在任何時候，無需解釋其決定”，宣佈任何外交人員為“不受歡迎人物”。