The unidentified individual had “several smart phones … and an appreciable sum of dollars” and was arrested by the Guards’ intelligence arm in the city of Karaj, west of the capital Tehran, the agency reported, citing its correspondent.

The latest arrest comes as Iran is set to release five Iranian-American detainees under a Qatar-mediated deal with the United States which will also include freeing five Iranians held by the United States and the unfreezing of $6 billion of Tehran’s funds that had been held in South Korea.

Iran’s elite Revolutionary Guards have arrested dozens of dual nationals and foreigners in recent years, mostly on espionage and security-related charges.

Rights groups have accused Iran of trying to win concessions from other countries through arrests on security charges that may have been trumped up. Tehran, which does not recognise dual nationality, says such arrests are based on its criminal code and denies holding people for political reasons.

The announcement was made during a military exercise off the coast of Abu Musa island, one of three Gulf islands under Iranian control but disputed by the United Arab Emirates.

The news agency gave no details about the missiles but cited a commander on the need to defend the islands.

“The islands of the Persian Gulf are part of Iran’s honour and we will defend them,” Revolutionary Guards’ Navy Commander Alireza Tangsiri said, adding that Gulf security needed to be provided by regional countries.

“The Persian Gulf belongs to all of the region’s countries … These states must be very prudent and prevent themselves from falling into the conspiracies and divisive plans of extra-regional countries,” he added.

Last month, the United States sent additional F-35 and F-16 fighter jets, along with a warship to the Middle East, in a bid to monitor waterways in the region following Iran’s seizure of commercial shipping vessels in recent months.