US intelligence agencies have placed diplomatic and military personnel on high alert amid warnings that Iranian threat plots targeting US personnel have advanced across the Middle East, Europe and the United States.
Director of National Intelligence Jay Clayton sent a memo to Secretary of State Marco Rubio warning that Iranian operatives have "substantially increased efforts to target US personnel". The memo said lethal plots in the Middle East and elsewhere had reached "advanced stages".
US intelligence officials assess that the threat to American citizens in the region is currently "at the highest level" since the start of the US-Israel war against Iran.
According to unnamed officials cited by The New York Times, Iran has assessed potential targets among senior officials, including ambassadors, and identified potential targets across Europe. Iranian operatives are also suspected of being active in the United States, although one official said Iran "lacks the capacity to follow through on all its ambitions".
US reduces diplomatic presence and repositions military assets
The US State Department has ordered non-essential staff to leave its embassy in Saudi Arabia, citing ongoing Houthi attacks and Iranian terror plots.
Staff numbers have also been reduced at US embassies in the United Arab Emirates, Bahrain, Kuwait, Qatar, Jordan and Lebanon.
Separately, the US military abruptly withdrew strategic bombers from RAF Fairford in the United Kingdom following a security breach and the arrest of several individuals by British police on suspicion of assisting Iranian intelligence.
The measures come as the United States and Israel are reportedly preparing for a renewed military campaign against Iran.
US President Donald Trump said Washington "may do another little epic fury", referring to the military operation launched on 28 February.
The Pentagon has confirmed that 21 US military personnel have been killed in the Middle East since the war began.
Iran signals a shift in military strategy
Iran has indicated that its response to any renewed conflict could extend beyond retaliatory strikes.
Islamic Revolutionary Guard Corps spokesman Hossein Mohebbi said Tehran was adopting a new "offensive" strategy, pointing to improvements in the range and precision of its missiles.
Senior Iranian security officials have also warned that, if hostilities resume, Tehran has plans to target undersea communications cables, regional data centres and artificial intelligence facilities across the Gulf.
The warnings suggest that critical digital infrastructure could become a target in a renewed confrontation, alongside military and diplomatic interests.
Previous alleged plots against US political figures
The latest intelligence warnings come against the backdrop of previous alleged Iranian-linked plots targeting American political figures.
In March, a court convicted a Pakistani national accused of plotting to assassinate Trump and other politicians under orders from the Islamic Revolutionary Guard Corps.
In 2022, an IRGC operative was charged with attempting to "pay individuals in the United States $300,000 to carry out the murder in Washington DC or Maryland" of former US national security adviser John Bolton.
US intelligence officials have also previously warned that Iran remains committed to targeting officials it holds responsible for the 2020 killing of Quds Force commander Qassem Soleimani.
The latest warnings, diplomatic staff reductions and military repositioning come amid uncertainty over whether the United States and Israel will resume military operations against Iran. The threat assessments also point to concerns about potential attacks on US personnel and interests beyond the immediate conflict zone.