Vessels report potential surveillance by unknown entities while in transit of the Gulf of Oman, Strait of Hormuz & Arabian Gulf.
In one recent case, a vessel was asked its crew complement and master's name, purportedly by a named vessel that was in fact operating elsewhere under the new name it has borne since 2011.
ONI [the Office of Naval Intelligence] cannot assess at this time whether the queries originated ashore or from vessels within the Gulf, but none is known to have been made by the vessel to which it was attributed.
Although these queries are not in themselves hostile, they are potential evidence of enhanced surveillance and could be a prelude to more specific interference; mariners are advised to be cautious about responding to them.
Detailed information about all such events should be reported to appropriate authorities including the Maritime Liaison Office Bahrain,
Source: Office of Naval Intelligence advisory dated 3 August - via Maritime Liaison Office Bahrain (MARLO Bahrain)