Article 11 Vienna Convention on Diplomatic Relations

1.In the absence of specific agreement as to the size of the mission, the receiving State may require that the size of a mission be kept within limits considered by it to be reasonable and normal, having regard to circumstances and conditions in the receiving State and to the needs of the particular mission.

2.The receiving State may equally, within similar bounds and on a non-discriminatory basis, refuse to accept officials of a particular category.

See also: Article 10 Vienna Convention on Diplomatic Relations