Article 45 Vienna Convention on Diplomatic Relations

If diplomatic relations are broken off between two States, or if a mission is permanently or temporarily recalled:

(a) The receiving State must, even in case of armed conflict, respect and protect the premises of the mission, together with its property and archives;

(b) The sending State may entrust the custody of the premises of the mission, together with its property and archives, to a third State acceptable to the receiving State;

(c) The sending State may entrust the protection of its interests and those of its nationals to a third
State acceptable to the receiving State.

See also: Article 44 Vienna Convention on Diplomatic Relations