Several foreigners were detained in Iran on Wednesday, including the United Kingdom's second most senior envoy in Tehran, as Iranian Revolutionary Guards carried out operations against alleged acts of spying such as taking soil samples from restricted areas, state television reported.

It did not say whether those detained were still under arrest.

"These spies were taking earth samples in Iran's central desert where the Revolutionary Guards' aerospace missile exercises were conducted," state TV said.

The TV showed footage of Giles Whitaker and his family in central Iran, where the British diplomat appeared to be taking ground samples. The TV said it was near an area where a missile test was taking place.

"Whitaker was expelled from (the area) after apologizing," the TV report said.

State TV identified one of those detained as the husband of Austria's cultural attache in Iran. It also showed a picture of a third foreigner, identifying him as Maciej Walczak, a university professor in Poland whom it said was visiting Iran as a tourist.

The TV report ran footage allegedly showing Maciej Walczak and three colleagues collecting earth samples in another area after visiting Iran on a scientific exchange program. It said their sample collection coincided with a missile test in Iran's southern Kerman province.

Iran's elite Revolutionary Guards have recently arrested dozens of dual nationals and foreigners, mostly over espionage and security-related charges.

Rights groups have accused the Islamic Republic of trying to win concessions from other countries through arrests on security charges that may have been trumped up. Tehran denies arresting people for political reasons.