British authorities have arrested several Iranian nationals in connection with an alleged plot to target “specific premises” in London, the Metropolitan Police announced on Sunday.

Police said five suspects, aged between 29 and 46, were detained on Saturday at various locations across England on suspicion of preparing a terrorist act. Four of the detainees have been confirmed as Iranian nationals.

Suspected Iranian IRGC agents arrested in the UK pic.twitter.com/QZJvH8RK4Q

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In a separate case, three Iranian men aged 39, 44, and 55 were arrested in London on suspicion of being involved in threat activity on behalf of Iran.

Police have stated that the two cases are unrelated, although details of the crime and arrests have not been disclosed.

“The investigation is still in its early stages and we are exploring various lines of inquiry to establish any potential motivation as well as to identify whether there may be any further risk to the public linked to this matter,” Commander Dominic Murphy, head of the Metropolitan Police’s counter-terrorism command said. 

He also urged the public to “remain vigilant” and to report any suspicious activity to the police.

Home Secretary Yvette Cooper called the arrests part of “major counter-state and counter-terror operations.” She thanked police and intelligence services and said the government is working to protect public safety.

The United Kingdom’s domestic intelligence agency has previously warned of rising threats from Iranian-linked actors in the U.K. Since 2022, the agency said it has disrupted 20 Iran-backed plots.