The ongoing U.S. strikes on Iran could have a ripple effect across the region, triggering a barrage of attacks from Tehran's proxy groups on American troops, allies and interests.
The likes of Hezbollah in Lebanon, the Houthis in Yemen and various Shiite militias in Iraq could be called on to target U.S. service members, civilians, ships, embassies and frequented hotels in the Middle East, threatening a wider regional war, experts say.
Hezbollah, considered the most powerful of Iran's proxies, is of particular concern to counterterrorism experts given its significant stockpiles of rockets and missiles -- even after Israel last year sought to decapitate its leadership.
"It's one of the more formidable non-state actors in the world, and so they still have capabilities to make life difficult," said Colin Clarke, the executive director of The Soufan Center. "The Hezbollah threat, I think, is the one that at least in the West, we probably worry about most."
But Hezbollah isn't the only Iran-backed actor that can cause serious damage. A former senior U.S. intelligence official, speaking on condition of anonymity, told The Hill on Friday that the Trump administration should be more worried about the Houthi rebels in Yemen, which the U.S. targeted during "Operation Rough Rider" last year.
As part of Rough Rider, Washington from March to May 2025 launched a major air and naval campaign against the Houthis following renewed Red Sea shipping attacks. But the campaign had difficulty destroying the group's underground arsenal of missiles, drones and launchers, and the Houthis quickly resumed attacks on commercial shipping.
"I would be more concerned about the Houthis going after oil infrastructure and then direct shots against the Israelis,"
the official said.
The U.S. and Israel began bombing Iran early Saturday morning after a third round of indirect nuclear talks between Washington and Tehran in Geneva, Switzerland, failed to satisfy the Trump administration.
Oman's foreign minister Badr al-Busaidi, who mediated the talks, claimed that Iran had agreed to give up its enriched uranium and allow U.S. inspectors access to nuclear sites.
But the Trump administration -- demanding that Iran end uranium enrichment in addition to limiting its arsenal of ballistic missiles and cut off its support of regional proxy groups that are designated as terrorist organizations by Washington -- decided it was through with negotiations and launched Operation Epic Fury.
Intended to spur regime change for Tehran, the military operation began with waves of strikes at 1:15 a.m. EST, utilizing Washington's massive military buildup in the Middle East -- the largest regional deployment since the invasion of Iraq in 2003 -- to hit Islamic Revolutionary Guard Corps (IRGC) command and control facilities, ballistic missile and drone launch sites, military airfields and Iranian air defense systems.
Trump said Iran's Supreme Leader Ayatollah Ali Khamenei was killed in a post Saturday afternoon, adding the U.S. bombing will continue "uninterrupted throughout the week or, as long as necessary."
Experts fear the U.S. attack on Iran could trigger a wave of retaliation against Israel and U.S. forces in the region, as well as on civilians.
Case in point, Saudi Arabia, Qatar, the United Arab Emirates, Bahrain, Jordan and Kuwait all appeared to have been targeted by Iranian attacks later on Saturday. All countries host U.S. bases or forces in the region.
Iran reportedly managed a strike against a service center of the U.S. Fifth Fleet naval base in Bahrain, and Qatar reportedly intercepted Iranian ballistic missiles targeting the Al-Udeid airbase in Doha, which hosts the U.S. Central Command.
Brett Velicovich, a former Army intelligence special operations soldier who served multiple tours in Iraq and Afghanistan, said if the U.S. opts for a sustained operation rather than quick strikes, Iran "would probably try and unleash their proxies to strike down targets in the region."
"If we've got some sustained operation like we did in Iraq and Afghanistan, which would be a major mistake, that would then give proxies the ammunition religiously to convince more people to help them and that's really where the danger is,"
said Velicovich, who now helps run the drone company Powerus.
He hypothesized that the groups would attempt to shoot American drones and maritime assets -- a capability the Houthis have already demonstrated -- assassinate diplomats, conduct kidnappings, and carry out other methods to "attempt to stoke a bit of chaos" in places where Iranians are prevalent, such as Qatar or the UAE.
"The reality is the Iranians do have their hands in a lot of different places,"
he said.
Clarke, of the Soufan Center, said he was concerned about U.S. embassies in Europe and hotels being prime targets for Iranian proxy groups.
"They often attempt to target civilians. So really, the target's head is limitless from that perspective,"
he said in an interview, adding that if there "true Hezbollah sleeper cells around the world, again, I think this would be the time when Iran would seek to use those, because the threat is existential."
The ex-senior intelligence official said the U.S. and other Western countries are monitoring for signs that Iran might direct proxies to conduct retaliatory strikes.
"It's a function of capability and intent. And in some cases, a lot of times, you have capability, but no intent. In this case, I would be looking at intent to actually execute and be part of this,"
they said.
Javed Ali, the former senior director for counterterrorism at the National Security Council, said he is worried about the relationship between Iran and Hezbollah, an Iran-backed Shiite militia, which has been at war with Israel since Oct. 7, 2023, as Hezbollah "has always been the most capable group" within Tehran's so-called Axis of Resistance.
"I think there is a serious threat of terrorism in the region,"
he said in an interview with The Hill.
Ali, who is now a professor at the University of Michigan, said the most dangerous organization within Iran, from a terrorist perspective, is the Quds Force, a secretive unit of Iran's IRGC, as they have trained, equipped and partnered with the Axis of Resistance now for decades.
"To me, that is Iran's ace in the hole when it comes to unconventional warfare, and they haven't used it against the United States, at least not outside of Iraq,"
he said.
Not everyone is as convinced that Iran's proxies pose a significant risk to U.S. forces and interests.
Velicovich said Iranian proxies may prove to be ineffective after being hammered over the past few years by Israeli strikes.
And Ret. Adm. William Fallon, a former commander of U.S. Central Command, told The Hill that Hezbollah has been quiet as of late and is "not in a great position" to strike American troops.
"I don't think any of them are in shape to do much right now,"
he said. "Hezbollah's got a lot of rockets [but] most of them are aimed at Israel. They're pretty much on the defensive, looking out for themselves."
As for proxies in Iraq and Syria, "I think [the U.S.] has pretty well reduced our footprint in both of those places," Fallon added.