TEHRAN, May 19, 2025 (AFP) - Iran has summoned a British envoy in Tehran to protest the arrest of several of its nationals on charges of spying, state media reported Monday.

"Following the unjustified arrest of a number of Iranian nationals in the UK... the British charge d'affaires in Tehran was summoned on Sunday," the IRNA news agency said, describing the arrests as "politically motivated".

Three Iranian men appeared in a London court on Saturday charged with spying for the Islamic republic.

They were arrested on May 3 and identified as Mostafa Sepahvand, 39, Farhad Javadi Manesh, 44, and Shapoor Qalehali Khani Noori, 55, all living in London.

The British Home Office said they were irregular migrants who arrived by small boat or other means, such as hidden in a vehicle, between 2016 and 2022.

The alleged spying took place from August 2024 to February 2025, according to UK police.

A fourth man was arrested on May 9 as part of the investigation, but has now been released without charge, the police said in a statement.

Five Iranians were also arrested on May 3 in a separate investigation.

Four of the men -- who had been held on suspicion of preparation of a terrorist act -- had been released, although the investigation "remains active and is ongoing", police said.

The fifth was earlier bailed to an unspecified date in May.