Army Gen. Michael “Erik” Kurilla, who leads U.S. Central Command, provides testimony in March 2023 at a Senate Armed Services Committee hearing at the Dirksen Senate Office Building in Washington. (John Wright/Department of Defense)

U.S. strikes in early February on Iranian proxies in the Middle East have deterred militant groups in Iraq and Syria from attacking American forces but have not been as effective against Houthi rebels in Yemen, the top U.S. general in the region said Thursday.

Iranian-backed militias in Iraq and Syria, including those responsible for the Jan. 28 drone attack in Jordan that killed three U.S. soldiers, have not fired at American troops in more than a month, Army Gen. Michael Erik Kurilla told the Senate Armed Services Committee. He credited the retaliatory strikes on some 85 targets in Iraq and Syria, including a drone strike on a top Kataib Hezbollah commander, with restoring an informal cease-fire in those countries.

“Iran has to understand there are consequences to their actions. I think that on that last attack that we did … our messaging matched our actions … and I think that sent a very strong deterrent message, and we have not had an attack in 32 days in Iraq or Syria,” said Kurilla, who leads U.S. Central Command and is responsible for American forces in the Middle East and central Asia. “But I will tell you deterrence is always temporary.”

The unofficial detente has come after a period that saw the Iranian-linked groups launch some 175 attacks on U.S. forces in Iraq and Syria after the Oct. 7 attack by Hamas militants on Israel. The surprise attack by Hamas militants raised tensions across the region as Israel launched a retaliatory war against Gaza, a Palestinian enclave. Kurilla described the Hamas attack as having “permanently changed” the region.

“It created the conditions for malign actors to sow instability throughout the region and beyond,” he said. “Iran exploited what they saw as a once in a generation opportunity to reshape the Middle East to their advantage.”

Blaming Iran for the uptick in violence throughout the region, Kurilla said the country should face more consequences for its actions. Neither the United States nor Iran, he added, wants to fight the other directly.

While violence has dropped in Iraq and Syria, it has increased off Yemen’s coast. Repeated U.S. strikes on Houthi rebels in Yemen, who are also backed by Iran, have not deterred the group from its attacks on commercial and military vessels in the Red Sea and Gulf of Aden, Kurilla said. The Houthis claim the attacks are in retaliation against those supporting Israel’s war in Gaza.

Near-daily strikes against the Houthis have been defensive in nature — taking out drones or missiles before they can be launched or once they are on the way toward a target, including U.S. Navy ships on several occasions, Kurilla said.

The Arleigh Burke-class, guided-missile destroyer USS Carney attacks a combination of Houthi missiles and unmanned aerial vehicles in the Red Sea on Oct. 19, 2023. (Aaron Lau/U.S. Navy)

The Houthis on Wednesday struck a commercial ship in the Gulf of Aden, killing three mariners in the first rebel attack that resulted in deaths. Another ship struck by the Houthis sank Saturday, weeks after it was hit by an anti-ship ballistic missile.

The Houthis’ weapons come from Iran, Kurilla said. While the United States has been joined by 24 other countries in efforts to protect commercial shipping vessels near Yemen, the general said more is needed to stop the illicit flow of advanced weapons from Iran to the Houthis.

“The most important thing is to deny their ability to resupply from Iran,” Kurilla said. “The Houthis are not building. They’re putting it all together and assembling, but they don’t create … medium-range ballistic missiles or the anti-ship cruise missiles.”

Several Republicans blamed President Joe Biden for being too soft on the Iranians for their actions in support of these proxy groups, including Hamas, Kataib Hezbollah and the Houthis. Sen. Dan Sullivan, R-Alaska, suggested the United States should attack Iranian vessels when they are found to support the Houthis.

The committee’s top Republican, Sen. Roger Wicker of Mississippi, called Biden’s military approach a “pinprick,” warning the relative calm in Iraq and Syria could end at any time.

“This approach has failed and will fail because it assumes that we can deter terrorist groups without causing pain to their chief sponsor — Iran,” he said.

But Democrats said Biden’s approach has balanced the need to protect U.S. troops and interests without dragging the region into an even broader conflict.

“Direct war with Iran would have devastating second- and third-order consequences and would likely engulf the entire region in war,” said Sen. Jack Reed, D-R.I., the chairman of the committee. “President Biden has balanced these considerations by synchronizing military operations with strong diplomacy, economic sanctions and other tools of statecraft.”

Kurilla declined to reveal what suggestions he has made to Biden, but he said he could use some help from Congress.

The general endorsed the national security supplemental bill passed last month by the Senate, but the legislation has not been considered by the House. That bill includes billions in aid to Ukraine and Israel, and it would funnel some $2.4 billion to support CENTCOM operations. Among his chief concerns, Kurilla said, was some $531 million in that bill that would support counter-drone defense systems for troops in the Middle East.

Kurilla said he worries a Houthi-fired drone or missile could sneak through the layered U.S. defensive shields and strike a Navy vessel. The extra money would bolster those efforts to protect American forces, he said.

Overall, American forces have been somewhat lucky that attacks in the region have only resulted in U.S. troops’ death once in recent months, Kurilla said.

“There are several incidents where [enemy drones] coming into a base hit another object or got caught up in netting or other incidents where had they hit the appropriate target that they were targeting it would have injured or killed service members,” the general said.

He also warned of problems elsewhere in the CENTCOM region.

“The risk of attack emanating from Afghanistan is increasing,” Kurilla said.

The instability in the Middle East has at times forced him to divert intelligence, surveillance and reconnaissance assets — primarily drones — from watching over Afghanistan, he said. The Islamic State’s Afghanistan affiliate, ISIS-Khorasan, continues to operate there and appears to be gaining momentum toward launching attacks on Western nations, Kurilla testified.

The threat appears to be limited, for now, to attacks in Europe or Asia but, if unchecked, could grow to include North America, he warned.

“I assess ISIS-Khorasan retains the capability and will to attack us and Western interests abroad in as little as six months and with little to no warning,” Kurilla testified.