The Biden administration has grown increasingly concerned in recent days that Israel’s enemies may seek to widen the war with Hamas by opening new fronts, a move that could force the United States to engage directly with air and naval forces to defend its closest ally in the region.
The administration sought to use diplomatic and military avenues to prevent any spread. The Pentagon sent a second aircraft carrier to the region over the weekend along with additional ground-based warplanes, even as Washington sent back messages to Iran through proxies in Qatar, Oman and China warning of escalation.
Fears of a second front deepened on Sunday as intense fighting broke out along Israel’s northern border. Hezbollah, the Iranian-backed militia that controls southern Lebanon, fired missiles at Israel, and Israel responded with artillery fire and airstrikes. A full-scale attack on the north could overwhelm Israel, as most of its forces are focused on a potential ground invasion of Gaza, to the south.
“We can’t rule out that Iran would somehow decide to engage directly,” Jake Sullivan, President Biden’s national security adviser, said on CBS’ “Face the Nation” on Sunday. “We have to prepare for all possible contingencies. That’s exactly what the president did. That’s part of what motivated the president to move these assets, to send that clear message of deterrence to make it clear that this war should not escalate.”
Some experts warned that such a scenario remains frighteningly possible as Israel’s vulnerability was exposed by a surprise attack by Hamas that killed more than 1,300 people, including at least 29 Americans. Hezbollah poses a far more serious threat to Israel than Hamas because of its vast arsenal of precision-guided missiles and thousands of experienced and well-trained fighters. Iran and Hezbollah may decide this is the moment of maximum opportunity to fight a wounded Israel, which is focused on returning the 150 hostages and destroying Hamas as a viable organization in Gaza.
Martin S. Indyk, former ambassador to Israel and special envoy for the Middle East, put the odds of a wider war at 50-50. “The potential to expand not only to Lebanon, but also outside of Lebanon is very high,” he said in an interview. “That’s why you see the administration so actively engaged in trying to defend them, which they wouldn’t have had to do if it hadn’t been for such a big deterrent blow to Israel.”
An Iranian close to the government said no decision had been made on opening a new front against Israel, but added that a meeting would be held Sunday night at Hezbollah’s command center in the Lebanese capital, Beirut, to discuss it.
After Hamas attacked Israel on Oct. 7, Iranian proxy militias across the region were put on high alert, as was Tehran’s military, according to two people familiar with Iran’s military calculations.
Iran itself has no plans to attack Israel unless attacked, the people said, but leaders of the so-called Tehran-backed Axis of Resistance have been debating whether Hezbollah should enter the war. The final decision, they added, may depend on what happens if Israeli ground forces enter Gaza as expected.
Iran’s foreign minister, Hossein Amir Abdollahian, was on a diplomatic tour of the region in Iraq, Lebanon, Syria and Qatar, countries linked to or friendly to Iran, Iranian state media reported. He openly demonstrated Iran’s support for Hamas by meeting with its political chief Ismail Haniyeh in Doha, Qatar. In Beirut, he also met with Hezbollah leader Hassan Nasrallah.
After Mr. Amir Abdollahian’s three-hour meeting with Mr. Haniyeh, Hamas representative Khalil al-Hayya said the two agreed to create a “broader front against Israel” and discussed how to prevent an expected Israeli attack on Gaza, according to IRNA, Iran’s state news agency.
“In my meetings with the resistance leaders,” said Mr. Amir Abdollahian, “I learned that when the time comes to respond to these crimes, it will determine and change the current map of the occupied territories.”
In his public statements over the past week, Mr. Biden has repeatedly made it clear that he stands firmly with Israel and has sought to send a clear message to Iran through military deployments. Last week he commissioned the Gerald R. Ford, the Navy’s largest and most advanced aircraft carrier, along with its escort group in the Eastern Mediterranean. Then on Saturday, Defense Secretary Lloyd J. Austin III ordered the carrier Dwight D. Eisenhower to join him.
The Air Force is similarly rushing more warplanes to the region, doubling the number of F-16, A-10 and F-15 squadrons on the ground. Combined with four squadrons of F/A-18s on each of the two carriers, the United States will have an air force of more than 100 attack aircraft, according to military officials.
The Pentagon also sent a small team of special operations forces to Israel to help with intelligence and planning to help locate and rescue hostages held by Hamas, which are believed to include some Americans.
Israel has historically resisted foreign ground troops participating in operations on its territory, and White House officials have said they are not considering any action by U.S. forces on the ground. But if Hezbollah launches a major attack, the United States could come to Israel’s aid by using naval and air units to bomb the militia in Lebanon.
“Moving two carriers to the region sends a very strong signal,” Gen. Frank McKenzie, retired commander of US Central Command, told “Face the Nation.” “There is a lot of historical evidence that Iran respects the flow of combat forces into theater. This affects their calculation of decisions. And as the Iranian calculation of decisions was affected, so was the calculation of the Lebanese Hezbollah.”
However, an Iranian close to the government said that US diplomatic messages sent through intermediaries indicate that the United States has no intention of going to war with Iran and that the warships are intended to provide moral support to Israel. This may indicate a difference in interpretation. US officials have said they do not want war with Iran, but are specifically sending military forces to deter Tehran with the option to use them if provoked.
Analysts questioned whether the message really got through. They said that the fact that Mr. That Biden felt compelled to send a second group of carriers suggests that the deployment of the first did not produce the kind of response from Iran that Washington expected or wanted.
Other US political leaders issued strong warnings to Tehran on Sunday. Senator Lindsey Graham, Republican of South Carolina, said that if Hezbollah launched a major attack on Israel, he would introduce legislation authorizing US military action in conjunction with Israel “to put Iran out of the oil business.” Speaking on NBC’s “Meet the Press,” Mr. Graham said: “Iran, if you escalate this war, we’re coming for you.”
Representative Michael McCaul, Republican of Texas and chairman of the House Foreign Affairs Committee, said the prospect of an escalation by Hezbollah was real and that direct Iranian involvement would be even more dire. “This is the nightmare scenario we’ve always been concerned about,” he told Fox News, adding, “That’s what worries me the most.”
The prospect of renewed military action in the Middle East comes after years in which the United States has sought to disassociate itself from so-called “perpetual wars” in Iraq, Syria and Afghanistan. At the moment, the United States is occupied helping Ukraine repel invaders from Russia, but not with American troops. That mission taxed American gun shops and sparked growing opposition from the far right.
With Mr. Biden’s request for $24 billion in additional aid to Ukraine stalled by House Republicans, the White House and congressional leaders are debating a broader security package that would combine money for Ukraine with aid to Israel. It would also include additional aid to Taiwan and funds for increased protection of America’s southwest border.
While all this could strain American resources, Mr. Biden said the United States could afford to help both Israel and Ukraine. “We can take care of both and still maintain our overall international defense,” he said in an interview that aired on CBS’ “60 Minutes” Sunday night. “We have the capacity for it and we have the obligation.”
As for his message to Iran and Hezbollah, Mr. Biden said it was simple: “Don’t, don’t, don’t, don’t.”
So far, the fighting on Israel’s northern border has been limited but alarming. Israeli emergency services said at least one Israeli civilian was killed and three wounded in Sunday’s attack on the border community of Shtula. Hezbollah said two of its fighters were killed in an Israeli counterattack.
In a statement, Hezbollah said its rocket attack was in response to the death of Reuters cameraman Issam Abdallah, along with two other civilians killed in recent clashes in southern Lebanon. The United Nations said its peacekeeping headquarters in Naqoura, Lebanon, had been hit by a missile, but it was not clear from whom. Peacekeepers were not in the shelters at the time and no one was injured, officials said.
After the exchange of fire, Israel’s military said it had designated a 2.5-mile area near the border with Lebanon as an “exclusion zone.” No one will be allowed to enter the zone, and any civilians already there must stay close to safe rooms in their homes, the military said.
“People are preparing for the worst,” said Shimon Guetta, chairman of the Ma’ale Yosef regional council, which oversees Shtulu. “After what happened in the south, residents are terrified it could happen again here.”
He contributed to the reporting Edward Wong, Eric Schmitt, Euan Ward and Aaron Boxerman.