Fifa World Cup matches set to be held across the United States face heightened terrorism risks, with experts warning that vulnerabilities are being amplified by the US-Israel conflict with Iran and a depletion of counter-terrorism expertise within federal law enforcement.

The biggest threat stems from homegrown violent extremists, often lone actors that may have become radicalized online by extreme political views or jihadists such as the Islamic State (Isis), said four counter-terror experts interviewed.

“We need to protect not only each venue, but all the other links in the chain that get to the point of the game,” said Javed Ali, associate professor at the University of Michigan, who previously served in the FBI, Department of Homeland Security, and as national security council senior director for counter-terrorism. “There are just so many games. There’s only so many resources to deploy to try to buy down risk against a number of different threats.”

In March, the FBI held a large residential training exercise on domestic threats, bringing together agents from across the country who work in domestic terrorism ahead of major national security events such as the World Cup.

When FBI agents at the meeting discussed the scale and complexity of securing the tournament, they were “alarmed, because there’s a lot that needs to be dealt with”, said one member of federal law enforcement in attendance, who spoke on the condition of anonymity. “It will be hard to control, given the environment and the number of locations of matches and watch parties across the United States. There is a very real possibility that something bad will happen.”

Although the US is experienced in securing large-scale stadium events such as the NFL Super Bowl, experts say the sheer number of World Cup matches will require an unprecedented level of coordination, vigilance and stamina.

The tournament will be about six weeks long, with 104 matches in the US, Canada and Mexico. The US will host 78 matches, in Atlanta, Boston, Dallas, Houston, Kansas City, Los Angeles, Miami, Philadelphia, the San Francisco Bay Area, Seattle and East Rutherford, New Jersey, which is about 10 miles from Manhattan.

The Department of Homeland Security has announced that only the final – which will be at MetLife Stadium in East Rutherford – will be designated as a ‘national special security event’ (NSSE).

The designation triggers a centralized federal operation led by the United States Secret Service, with intelligence from the FBI and emergency coordination by the Federal Emergency Management Agency (Fema). It includes hardened security perimeters, magnetometer screening, temporary flight restrictions enforced by the Federal Aviation Administration, counter-drone systems and continuous counter-terrorism monitoring across federal, state and local agencies.

The other matches will be designated a special event assessment rating (SEAR) 1 or 2, which are the two highest risk rankings for events and also require the deployment of federal law enforcement.

Fema has allocated $625m to support security and emergency preparedness for the World Cup. While all stadiums hosting matches are considered “hard targets” due to extensive security measures, counter-terrorism experts say the greater concern lies with “soft targets” – including hotels, transportation hubs and fan gatherings across the country.

“Planning to protect the Fifa World Cup 2026 has been going on for many months and the FBI continues to work closely with our federal, state, and local law enforcement partners. The games are taking place around the country and require the work of many partners to ensure the safety of those in the stadiums, as well as the surrounding communities,” an FBI spokesperson said in a statement to the Guardian.

A spokesperson for the Department of Homeland Security said: “DHS is working around the clock with our federal, state, and local law enforcement partners to identify and mitigate potential threats to World Cup matches, fan fests, and to a travel sector that will see a dramatic increase in traffic. DHS is cognizant of lone wolves and small cells inspired to commit violence, as the DHS Office of Intelligence and Analysis is working closely with state, local, tribal, territorial, and private sector partners to keep them apprised of the latest and most relevant threat information available.”

Lone actors and ‘soft targets’ heighten risk

All 11 host cities will host official Fifa fan festivals, with large-screen broadcasts, concerts and live entertainment running throughout the tournament. Thousands of additional watch parties at bars and venues across the host countries will extend crowds well beyond stadiums and official sites.

“We’re still going to have densely populated crowds waiting outside of stadiums. There will be the vulnerability of drones, which are ubiquitous, easily mastered by individuals or non-state groups, including terrorist groups,” said Colin Clarke, director of research at the Soufan Group, an intelligence and security consulting firm based in New York City.

Experts say the challenge is not only protecting potential targets, but ensuring coordination across the agencies responsible for securing them.

“What I’ve seen is that we have lapses in our security when different agencies, such as Homeland Security, FBI, and our regional local police officers, fail to communicate with each other,” said Tracy Walder, a former CIA and FBI special agent who was working at the CIA in 2001 during the 9/11 attacks. “That’s probably our biggest problem.”

The 2024 assassination attempt against Donald Trump on the campaign trail in Butler, Pennsylvania, and the 6 January 2021 fatal siege on the Capitol in Washington DC were examples of these types of communications breakdowns, she said.

The World Cup is especially vulnerable because of the current conflict with Iran, which has historically been linked to attempted attacks on US targets, said the experts interviewed.

The potential for an Iran v United States match in Texas on 3 July on the eve of Independence Day, coupled with the expected heavy presence of the Saudi royal family, who have booked out an entire hotel in Houston for the tournament, raises additional concerns, said the federal law enforcement source. Saudi Arabia and Iran are longstanding regional rivals with a history of deep geopolitical and sectarian tensions.

“You have the Saudi royal family in close proximity to where Iran and the United States would be playing, it’s like adding gas on the fires,” said the source.

Yet, concerns over so-called “sleeper cells” – foreign terrorists that are embedded in the country and stay dormant for a period of time before launching an attack – may be overblown, some experts said.

“The Iranians just don’t have the people here to pull off an attack,” said Ali. “If people who are actually trained or formally associated or linked to Iran’s Quds Force were here and wanted to conduct these attacks, why haven’t they tapped into those networks?”

In the past, Iran-backed terror plotters have needed to co-opt the criminal underworld here in United States and contract these attacks out to intermediaries such as professional criminals, Ali said.

Murder-for-hire plots, such as the 2022 assassination attempt on former national security adviser, John Bolton, which was attributed to an Iranian man who is allegedly a member of the Islamic Revolutionary Guard Corps (IRGC), are examples of this tactic. The IRGC has also orchestrated several assassination attempts against the New York-based Iranian dissident, Masih Alinejad. One foiled plot in 2022 involved two members of a Russian mob who were hired to murder her in her Brooklyn home. In January, another convicted murderer from Brooklyn was sentenced to 15 years in jail for a failed plot to murder Alinejad in exchange for $100,000.

These types of attacks are becoming more common since the outbreak of the US-Israeli war on Iran in late February. In the past few months, British authorities have uncovered a series of Iran-linked plots in London in which operatives allegedly used criminal intermediaries, who are often recruited online, to carry out attempted attacks and assassinations against dissidents and political targets.

“Luckily, a lot of those are very amateurish, because they aren’t trained operatives. They may not even be regime supporters,” said Clarke.

Experts warn that homegrown extremists acting alone pose one of the most immediate and difficult-to-detect threats.

“Right now we’re living in a heightened threat environment,” Walder said. “You can’t kill an idea. You can take out leadership, but they’re just going to replace themselves. The idea isn’t ever going to die … We’re just a few steps away from the next big attack.”

Recent attacks underscore the threat. In April, a lone gunman targeted the White House correspondents’ dinner. On 1 January 2025, a man drove a pickup truck into a crowd on Bourbon Street in New Orleans, then opened fire, killing 14 people and injuring dozens more; an Isis flag was later found in the vehicle. In March, an attacker with a prior Isis-support conviction opened fire on a Reserve Officers’ Training Corps (ROTC) class at Old Dominion University, killing one instructor and injuring two cadets before being subdued.

“I don’t think this administration is taking counter-terrorism seriously enough. Resources have been shifted to other portfolios,” said Clarke. “The authorities let an Isis guy just roam free, acquire a firearm and then try to kill ROTC students. But they have ICE agents in Home Depot parking lots trying to pick up [undocumented] landscapers. The priorities are a bit mixed up here.”

New threats and intelligence gaps

Alongside human threats, security officials are increasingly focused on emerging technological vulnerabilities. While the skies above the stadiums will be no-fly zones, other mass gatherings could be vulnerable to drone attacks, said experts interviewed.

“We’ve also seen terrorist groups over the years express interest in using drones, and talking about this on message boards,” said Clarke. “I think it’s only a matter of time before we experience a terrorist attack on US soil with the drone involved.”

“In the past, it’s always been about protecting the venue or the people there,” said Javid. “And now what the [Washington] Hilton [correspondents’ dinner] attack shows there’s like a whole supply chain that has to be looked at as well.”

Walder worked on counter-terrorism programmes focused on biological and chemical terrorist weapons during her time at the CIA, and believes the authorities have an understanding of those types of threats, she says. To her, some of the most concerning types of threats would be cyber or technological, “simply behind because we just don’t have the manpower that like Russia or China has”, she said.

“We are in a very different place, technology wise, than we were in 2001, and so it takes less people to inflict maximum damage,” she said.

In February, US counter-terrorism efforts were dealt a further setback with the firing of a Washington-based FBI counterintelligence unit, CI-12, which tracked foreign spies and terrorism threats on the US. They were ousted in retaliation for their involvement in the investigation of Trump’s alleged retention of classified documents at his Mar-a-Lago estate, according to reports.

“Many folks have lost their jobs, and some for reasons that aren’t exactly clear, which don’t seem to be performance based,” said Ali.

Ali warned that maintaining a clear intelligence picture across agencies monitoring Iran-related activity was essential to detecting early signs of potential threats.

“My hope is that these decisions that are being made are not contributing to the inability of the FBI that to execute its national security missions,” said Ali. “Because that makes the country less safe.”

An FBI spokesperson said, “While the FBI does not comment on specific personnel numbers or decisions, FBI agents and staff are dedicated professionals working around the clock to defend the homeland and crush violent crime. The FBI continuously assesses and realigns our resources to ensure the safety of the American people, and we surge resources based on national security needs.”