An Iran-backed trio is accused of plotting attacks on a U.K. base hosting U.S. jets

Prosecutors allege the men acted on behalf of Iran's Islamic Revolutionary Guard Corps and the Iraqi militia Kata'ib Hezbollah to orchestrate, plan and conduct the attacks through a network of associates across Europe and the U.S., targeting Jewish communities and a British base hosting American troops. The indictment cites plots against synagogues in London and in New York. Both Iran's Revolutionary Guard and Kata'ib Hezbollah are designated by the United States as foreign terrorist organizations.

The court filings describe an operation that was directed, in part, by the suspects who were thousands of miles away. In April, prosecutors have alleged, the three men gathered in a room and watched an attack unfold live on a large screen via Apple's FaceTime video calling app. Al-Hassani allegedly coached the attacker through igniting and hurling a series of seemingly incendiary devices while Al-Saadi filmed.

The following day, Al-Hassani is accused of guiding another man on a video call as he lit an improvised explosive and threw it at a synagogue in London.

The men "helped orchestrate a campaign of terror" on behalf of the two designated terror groups, according to U.S. Attorney for the Southern District of New York, Jamie McDonald.

The RAF Fairford plot

The United Kingdom seems to have been a central target of the plot allegedly perpetrated by the three men: among the roughly 18 attacks claimed last spring by a group calling itself Harakat Ashab al-Yamin al-Islamiya, which prosecutors say was a front for Kata'ib Hezbollah, as many as seven took place in the U.K. It was the most intensely targeted country in Europe, though the indictment does not specify the location of other plots or attacks.

These included arson attacks, the use of explosives, and a near-fatal stabbing of two Jewish men in London — one of whom was a dual U.S.-British citizen.

Prosecutors say that in April the men sat in a room, and directed an attack remotely, in real time, over FaceTime, telling the attacker when to light and throw what seems to have been some kind of incendiary device.

The next day, one of the men, Mohammed Ali Al-Hassani, allegedly told another man attacking a London synagogue to "light it up like a Christmas tree."

According to the indictment, Al-Hassani was operating from Iran, but he began paying associates in Britain in August to film the perimeter of Royal Air Force (RAF) Fairford, in Gloucestershire, several hours west of London.

They allegedly obtained vans and drums of fuel, looked into buying chemical accelerants, and gathered metal items that could potentially serve as shrapnel. The vans were fitted with sham branding for a fuel delivery firm as well as a pool supply company.

On Sept. 26, three of these vans had set off toward the base that housed large numbers of U.S. military aircraft. At least two vehicles were stopped at a security roadblock, and British authorities seized all three early the next morning and arrested those inside.

The U.S. almost immediately redeployed several of its long range bombing aircraft from the base at the time of this incident.

The indictment said Al-Saadi had been detained abroad in May and brought to the United States, where prosecutors say he kept directing the network from his jail cell by relaying coded messages through phone calls with relatives in Iraq. He used aliases to refer to his alleged co-conspirators and referred to terrorist activity, including ongoing alleged plots, as "work," while those he spoke to used the phrase "international section" to mean overseas travel, according to the indictment. His sister and mother were among his interlocutors on some of those calls. Three days before the plot, in late September, he allegedly asked them to get money to Al-Hassani for the RAF Fairford operation.

British authorities had earlier charged two men with national security related offenses tied to the incident.

U.S. soldier held over Russia allegations

In a separate case, British counterterrorism police said on Tuesday it arrested a 41-year-old member of the U.S. Army on suspicion of offenses under Sections 1 and 3 of Britain's National Security Act 2023.

The suspect, who has not been named by authorities, is a senior U.S. soldier who was stationed at Imjin Barracks near Gloucester, in western England, which is home to NATO's Allied Rapid Reaction Corps, the U.S. Army's Counterintelligence Command told NPR.

Officers have been searching two addresses in the same region of Gloucestershire, to the west of London. The man is being held at a London police station. Police said the allegations concern Russia, and the investigation was "very much ongoing," according to Deputy Assistant Commissioner Vicki Evans, senior national coordinator for counterterrorism policing in the U.K.

FBI Director Kash Patel called the arrest important in the context of an uptick in FBI counterintelligence arrest, and said it "involves allegations of espionage" — without giving further details.

"The alleged conduct of a senior soldier, entrusted with sensitive information, is a sobering reminder that insider threats are real and persistent," Brig. Gen. Sean Stinchon, commanding general of U.S. Army Counterintelligence Command, said in a statement to NPR.

The U.S. footprint in Britain

Though unrelated, both these cases have occurred in the U.K., a country which hosts a large American military presence. At the start of the war in Iran, Britain's Defense Ministry confirmed to the U.K. Parliament in March that U.S. forces operate eleven RAF bases across the country, with approximately 12,300 American military and civilian defense personnel at various sites.

Responding in January to a written question from a member of Parliament, the ministry said that there were around 11,000 uniformed U.S. personnel in the country, excluding families, civilians and contractors.

The ministry has declined to give figures for individual bases, citing the security of personnel.

The U.S. Air Force's two main operating bases are RAF Lakenheath and RAF Mildenhall in Suffolk, in eastern England. Other sites include RAF Croughton, a communications station in Northamptonshire, and RAF Menwith Hill in North Yorkshire, used primarily by the National Security Agency, according to a House of Commons Library briefing. RAF Fairford serves as a forward operating base for the U.S. Air Force Global Strike Command.

In March, the British government allowed the U.S. to use British bases for limited strikes against missile sites in Iran, according to a parliamentary research service, which identifies Fairford as one of the bases potentially involved.

The threat picture around some U.S. bases seems to have sharpened in recent days. The Wall Street Journal reported, citing people familiar with the matter, that the U.S. military had moved aircraft out of RAF Mildenhall on Monday because of a threat from Iran. NPR did not independently confirm the reports.

Neither the U.K. nor the U.S. government has confirmed the reason for the aircraft movements that have been reported. Britain's Defense Ministry has said aircraft relocate routinely for operational reasons.