Houthi Media Center/AP
This photo released by the Houthi Media Center shows Houthi forces boarding the cargo ship Galaxy Leader on Sunday, Nov. 19, 2023.
CNN  — 

US officials are grappling with how to respond to escalating attacks by Iran-backed proxy groups on US troops and ships in the Red Sea without sparking a broader war in the Middle East.

The US has retaliated several times to the proxy groups’ attacks, striking militants and infrastructure in Iraq and Syria and shooting down missiles and drones launched by the Houthi rebels in Yemen. US officials have also conveyed to Iran and its proxies via backchannels that the attacks must stop, and on Sunday the US killed a group of Houthi militants attempting to board and seize a commercial vessel in the Red Sea.

A senior administration official said the US would not hesitate to use lethal force again against the Houthis in self-defense. “If that happened again, we would probably do the exact same thing,” the official said.

But the US has been deeply reluctant to move beyond self-defense strikes and backchannel diplomacy, even as the Pentagon has drawn up various options for President Joe Biden to strike the Houthis inside Yemen should he choose that approach, officials told CNN.

Since Israel launched its war against Hamas in Gaza following the terror groups’s October 7 attack, the US has been scrambling behind the scenes to prevent a broader multi-country war from igniting. But the challenge has only increased with tensions skyrocketing this week following an Israeli strike on a Hamas leader in Lebanon and a major ISIS terror attack in Iran on top of the regular Iranian proxy attacks.

“We remain incredibly concerned, as we have been from the outset of this conflict, about the risk of the conflict spreading into other fronts,” State Department spokesperson Matthew Miller told reporters on Wednesday.

Wary of undercutting Yemen truce

The US has been particularly wary of undercutting a US and UN-brokered truce between Saudi Arabia and the Houthis over the war in Yemen that the Biden administration considers one of its crowning foreign policy achievements, a senior US official said. Some in the administration, moreover, believe the Houthis thrive at war and want to draw US forces into a prolonged engagement. A yearslong Saudi-led campaign against the Houthis did not eliminate the rebel group, officials have pointed out.

Another senior US official said the Houthis are already alienating countries “whose support is crucial for a peace deal in Yemen.”

“Houthi actions threaten to turn Yemen into a pariah state,” the official said. “Yemeni civilians will suffer most from the international isolation that will result if attacks continue.”

If left unaddressed, however, the ongoing Houthi attacks on commercial shipping in the Red Sea could further ensnare global trade and undermine Biden’s ability to sell a strong economy heading into the 2024 election.

The risk of an Iranian response, while less likely, is also an ongoing concern, officials said. Iran deployed a warship to the southern Red Sea this week in an apparent show of support for the Houthis, just one day after the US Navy killed the group of Houthi militants attempting to board and seize a commercial vessel. Iran has also been providing weapons and intelligence to the Houthis, CNN previously reported.

Even in Iraq, where the US has been more willing to take direct action against Iranian militias who have targeted American troops, White House officials are mindful of how the actions will anger the Iraqi government. Several Iranian proxy groups in Iraq have political wings that have formed a governing coalition in Baghdad, adding to sensitivities about going after the militias.

US military installations in Iraq also rely on the invitation of the country’s government, lending a degree of complexity to how Biden decides to target the militias.

Patience running thin

There are signs, though, that the US and its allies’ patience is wearing thin.

Last month, Secretary of Defense Lloyd Austin announced a multinational security initiative – “Operation Prosperity Guardian” – to respond to the increased Houthi aggression in the Red Sea.

On Wednesday, a senior US administration official said that a joint statement by the US and 12 other countries condemning the Houthi attacks on shipping was likely the coalition’s last warning—signaling that more forceful military action could soon follow.

Indirect backchanneling to Iran to try to deter a wider conflict in the Middle East will be a key focus of Secretary of State Antony Blinken’s trip to the region over the next few days, a senior State Department official said Friday.

The top US diplomat will make clear to the leaders he meets that the US does not want to see the conflict escalate nor do they intend to escalate it.

The US expects that message to then be conveyed to Iran and the Iranian proxies via the countries that have a relationship with them, the official said.

Blinken, “will make it clear on all of his stops that the Houthi attacks are unacceptable,” Miller said on Thursday.

“Action will be taken” if the attacks continue, British Foreign Secretary David Cameron told reporters on Thursday, indicating that British ships would be used to stop the attacks if necessary.

It does not appear the Houthis have heeded the warnings. The rebels launched yet another attack on shipping on Thursday using an unmanned surface vessel, which traveled from Yemen into international shipping lanes “clearly with the intent to do harm” before detonating, said Vice Adm. Brad Cooper, the commander of US Naval Forces Central Command. Cooper also said the Houthi attacks showed no signs of abating.

Also on Thursday, the US targeted and killed a pro-Iran militia commander in Baghdad—the second US strike on Iranian proxies in Iraq in just over a week, despite the Iraqi government calling such strikes a violation of their sovereignty.

Further underscoring the delicate balancing act the US has been engaged in in the region, US officials did not condemn the apparent assassination by Israel of a senior Hamas leader in Lebanon, even as hostilities between Israel and the Lebanese militant group Hezbollah risked escalating even further over the killing. Privately, US officials say the targeted killing mirrors how the US targets terrorist leaders in drone strikes around the world.

But the White House did dispatch a senior envoy, Amos Hochstein, to Israel on Thursday to try to calm tensions between Israel and Lebanon.

Hochstein has been shuttling between the US and Israel for months, working with the Israeli and Lebanese governments to try to reach a diplomatic solution to the violence and prevent the war from expanding to a new front on Israel’s northern border. But Israeli officials told Hochstein on Thursday that the window is quickly closing for a peace deal.

“Israel is willing to work closely with the US and the international community to achieve a diplomatic solution, but if one cannot be found – the IDF will remove the threat,” Israeli War Cabinet member Benny Gantz told Hochstein, referring to the Israel Defense Forces.

On his trip, Blinken will make a stop in Israel, where he is expected to discuss the nation’s plans to transition to a lower-intensity phase of operations in Gaza and how to stem the spread of the conflict, which will be an overriding theme of the whole trip. The top US diplomat will discuss “specific steps parties can take including how they can use their influence with others in the region to avoid escalation,” Miller said on Thursday.

“We don’t expect every conversation on this trip to be easy,” Miller added.

CNN’s Jennifer Hansler, Alex Marquardt MJ Lee contributed reporting.