Iranian dissidents in the UK have warned that Tehran is growing “more aggressive and dangerous” overseas as it emerged that the Israeli embassy in London was the target of a major alleged terror plot.

Four Iranian men are being questioned by police on suspicion of planning to target what police have only described publicly as a “specific premises”.

However, multiple sources said Israel’s embassy in Kensington, west London, was the building in question. A spokesperson for the embassy declined to comment when contacted on Thursday morning.

The arrests on Saturday followed a police and MI5 operation into what Dan Jarvis, the security minister, described in the Commons as “largest counter-state threats and counter-terrorism actions we have seen in recent times”.

Three other Iranian men are also being questioned on suspicion of being involved in “foreign power threat activity”, in this case understood to be on behalf of Iran.

Iran’s foreign affairs minister, Seyed Abbas Araghchi, said his government denied any suggestion of being involved in targeting the Israeli embassy.

In a post on X on Wednesday night, Araghchi said: “Iran in no uncertain terms categorically rejects any involvement in such actions and confirms that we have not been informed of any allegations via proper diplomatic channels.