A diplomatic courier is an official who transports diplomatic bags as sanctioned under the 1961 Vienna Convention on Diplomatic Relations. Couriers are granteddiplomatic immunity and are thereby protected by the receiving state from arrest and detention when performing their work. Couriers may be assigned on an ad hoc basis, but in those cases they are released from immunity once their bags have been delivered. All couriers are provided documentation that reports their status as couriers and the number of packages currently being transported in the diplomatic bag. Diplomatic bags may be transported under the authority of commercial airline captains, but they are not diplomatic couriers.