British police said on Saturday that three Iranian nationals have been charged under the National Security Act with a plot to attack an individual on behalf of Iran.
A statement said the London-based men were engaging in conduct likely to assist a foreign intelligence service.
The investigation, led by counter-terrorism officers of the Metropolitan Police, has been continuing since May 3.
The men were named as Mostafa Sepahvand, 39, of St John’s Wood, London, Farhad Javadi Manesh, 44, of Kensal Rise, London, and Shapoor Qalehali Khani Noori, 55, of Ealing.
Mr Sepahvand was also charged with engaging in conduct, namely surveillance, reconnaissance and open-source research as part of efforts to conduct an act of violence against a person.
A fourth man arrested a week ago in connection with the same allegations was released on Thursday.
The statement said the foreign state to which the charges relate is Iran.
“These are extremely serious charges under the National Security Act, which have come about following what has been a very complex and fast-moving investigation,“ said Commander Dominic Murphy from the Met’s Counter Terrorism Command.
Iran has denied links to two separate sets of arrests in the UK, including a reported plot to attack the Israeli embassy. Iran's Foreign Minister “categorically” rejected the reports of a plot to attack the Israeli embassy in London.
An unrelated set of raids five people round up another Iranian-linked plot involving suspects across the UK.
That group was arrested on suspicion of preparing an act of terrorism and allegedly belong to Unit 840, which carries out assassination and kidnapping missions for Tehran's Islamic Revolutionary Guards Corps.
Two men aged 29 were detained in Swindon in Wiltshire and Stockport in Cheshire, a 40-year-old was held in Rochdale, Greater Manchester, a 46-year-old in west London and a 24-year-old was detained in the city of Manchester.
Reports have identified the Israeli embassy in Knightsbridge as the target of the alleged plotters and officials have claimed the attack was imminent.
The use of Iranian nationals in an alleged terrorist plot is thought to represent a change in tactics from Tehran’s preference of hiring criminals.
This year, the government placed Iran on the highest tier of the new foreign influence register, requiring it to register everything it does to exert political influence in the UK.
