As the US sends large numbers of troops to the Middle East, preparing for a possible ground incursion, Iran’s willingness to inspire lone-wolf attacks, lead cyber hacks, and conduct assassination operations abroad is likely to increase, terrorism experts and US law enforcement officials told CNN.

In the early days of the war, officials raised concerns that Iran might activate “sleeper cells,” a kind of covert agent who has sat undetected in the US waiting for an order to carry out a terror plot. But in recent years, Iran has instead depended heavily on an everything-and-the-kitchen-sink approach to attacks abroad — with a key focus on inspiring domestic attacks and, at times, working to hire known criminals to assassinate its enemies, several experts told CNN.

The Justice Department has foiled several assassination plots in recent years, including against President Donald Trump, top US officials and Iranian dissidents. In those cases, Iranian officials, often through proxies, have hired low-level criminals — sometimes recruiting from inside US prisons — to act on their behalf.

In early March, a Pakistani man was convicted of attempting to carry out political assassinations in the US, including against Trump, at the direction of Iran. The man, Asif Merchant, met with undercover agents he believed were hitmen in the summer of 2024 to carry out these attacks before being arrest by federal authorities.

Iranian assassination plots targeting Israeli officials have also been foiled, including one late last year against the Israeli ambassador to Mexico.

Iran additionally — through social media channels, chatrooms and beyond — works to inspire lone wolf attacks of vandalism and violence across the globe, something William Wechsler, a former US deputy assistant secretary of defense for counternarcotics and global threats, said is cause for concern.

“I’m more concerned about the actively recruited, ideologically aligned-people, and I’m more concerned about the lone wolves who are ideologically aligned,” Weschler, who is now the director of Middle East programs at the Atlantic Council, said.

Wechsler added that the threat of ideologically aligned lone wolf actors is higher than when criminals are recruited.

“The criminal ones could work, but they’re going to have a very high percentage of failure rate,” he said.

The US was hit with four terrorist attacks in the first week of the conflict with Iran, officials say, including a mass shooting in Austin, Texas, that left three dead and an attack on a Jewish synagogue and school in Michigan where a Lebanese-born man rammed a car through the front lobby and died after a gun fight with security.

Investigators say the assailant in Austin wore a t-shirt with the Iranian flag and had other items they believe indicate he was motivated at least in part by the recent conflict. He was also suffering from mental health issues, investigators told CNN.

Prior to the Michigan attack, several members of the attacker’s family were killed in Israeli strikes in Lebanon, which investigators believe played a large part in his motivation. Israeli officials say the man’s brother was a Hezbollah commander in charge of managing weapons operations in the Iranian proxy group’s Badr unit. US investigators have not confirmed those claims.

These lone wolf attacks, a grave concern for federal law enforcement, have been far more deadly than the organized plots arranged by Iran or its proxies. Experts told CNN that these and similar efforts by the Iranian government are only set to escalate as the conflict with Israel and the US drags on.

The United Kingdom has also seen recent attacks in the wake of the conflict, including an arson attack on a Jewish community earlier this month.

The UK has disrupted more than 20 Iran-backed terror plots in recent years, many of which involved Iranian operatives looking to hire attackers, some through the dark web, to target Jewish institutions and Iranian dissidents, London police commissioner Sir Mark Rowley told CNN in a recent interview.

While far less of a concern than these other forms of attacks, Iranian-backed sleeper cells are still on the minds of law enforcement officials.

That concern has been diminished in recent years as Iran’s capabilities beyond the Middle East region to inflict such terror attacks has been limited, experts say.

“The threat across the Gulf is quite high,” Wechsler said of such actors, adding that because the US has not seen these types of attacks in the weeks since the war began, the likelihood of such groups or people operating in the US has decreased.

“Doesn’t mean it’s zero,” he said. “I wouldn’t be complacent on the whole thing.”

Dr. Colin P. Clarke, the executive director of the Soufan Center whose research focuses in part on domestic and transnational terrorism, warned that when it comes to foreign attacks, Iran is more than capable of playing the long game.

“This isn’t something you just put into motion the next day,” Clarke said of potential sleeper cells directed by Iran. “If somebody’s been living in the United States with this intent, this is a long-term plan. They don’t have to operationalize it the next day.”

Clarke added that “we don’t know what their threshold is to use that capability, if they have it. We know they have the intent. There’s no doubt about that.”

“The question is, if they have the capability, what causes them to operationalize it?” Clarke said.

Clarke and Wechsler also warned that terrorist groups such as ISIS have and will use the war and mounting anger against the US and others to push their own attacks.

“Even though ISIS has no love for Iran, there’s real sectarian hatred,” Clarke noted, adding that if the US were to run a ground invasion and take over the country “it’s going to inflame the entire Muslim world.”

When it comes to fighting terrorism, Wechsler said, “the most important thing we can do against any terrorist narrative is actually defeat them in the real world.”

“Because if they are seen to be successful, then all of these problems that I just described — lone wolf terrorism — actively go up exponentially,” Wechsler said. “If they’re seen to be losers … then a lot of this stuff naturally goes down because people don’t want to join a loser.”