The sounds of battle echo on both sides of Israel’s northern border with Lebanon. Sirens blare in Israeli towns, warning of incoming rockets fired by Lebanon’s Hezbollah militant group. Lebanese civilians have fled their villages, fearing Israeli shelling and the possibility of a new war.
Since Hamas launched its deadly attack in southern Israel, tensions have surged along Israel’s northern border, increasing fears of a new conflagration between Israel and Hamas’s Iranian-backed ally Hezbollah in neighboring Lebanon.
Such a war poses great risks to everyone involved, experts say. Israel, which appears poised to launch a ground invasion in Gaza, could struggle to fight on two fronts and defend itself against Hezbollah’s skilled guerrillas. Lebanon, already reeling from a deep economic crisis, could face intense Israeli airstrikes that destroy infrastructure and could kill large numbers of people.
The potential for international involvement raises the stakes even further. The United States has dispatched two aircraft carriers to the Mediterranean in support of Israel that could strike targets on land. And other groups in the so-called axis of resistance, the network of Iranian-backed forces across the Middle East, could be drawn into a new war.
“The calculations in great wars are not calculations about states,” Gen. Abbas Ibrahim, Lebanon’s former security chief, said in an interview on Monday. “This is a war of existence: Either Israel remains or this axis remains.”
Leaders on both sides of the divide have issued stark warnings, emphasizing the stakes.
On Monday, Prime Minister Benjamin Netanyahu of Israel told Hezbollah not to get involved. “I have a message for Iran and Hezbollah: Don’t test us in the north,” he told Israeli lawmakers. “Don’t repeat the same mistake, because today, the price you’ll pay will be much heavier.”
Iran’s foreign minister, Hossein Amir-Abdollahian, warned in an interview on Iranian state television late Monday that Iran’s allied regional militias could attack Israel if it continued its attacks on Gaza.
“Time is running out very fast,” he said. “If the war crimes against the Palestinians are not immediately stopped, other multiple fronts will open and this is inevitable.”
One motivation for the Biden administration’s bringing the aircraft carriers closer to Israel is to try to convince Hezbollah to stay out of the fighting to avoid any possible intervention by the United States.
Changes in the Middle East in recent years have made it more likely that violence in one place could ignite violence elsewhere. That’s because Iran has worked to knit anti-Israel forces in different countries into an increasingly tight web.
Armed groups in Gaza, Lebanon, Syria, Iraq and Yemen that once largely fought separately now see themselves as being on the same team. Many of their commanders have received similar training from Iran or Hezbollah and their members share knowledge on how to increase the firepower of rockets and to surveil their enemies with drones.
Iran may lead the network, but Hezbollah, which was formed in Lebanon by the Islamic Republic more than three decades ago, is the primary enforcer. Its members played a key role in helping Syria turn the tide against anti-government rebels during the country’s civil war, which began in 2011. And its operatives have increased the fighting abilities of pro-Iranian militias in Iraq and the Houthi rebels in Yemen. Israel, the United States and other countries have designated Hezbollah and some of its regional partners, including Hamas in Gaza, as terrorist organizations.
Israel has viewed Hezbollah as its most formidable foe since they fought to a standstill in a monthlong war in 2006 that killed more than 1,000 Lebanese and 165 Israelis. Hezbollah’s members are highly trained, have an arsenal of tens of thousands of rockets and possess precision-guided missiles that can pummel targets deep in Israeli territory.
While Hezbollah’s precise capabilities are unknown, analysts say they have increased substantially since 2006, partly because its members gained experience fighting the jihadists of the Islamic State in Syria and Iraq.
Hezbollah’s arsenal, which includes air-defense capabilities, makes it much more dangerous to Israel than Hamas, the Palestinian group that controls the Gaza Strip, said Orna Mizrahi, a retired Israeli deputy national security adviser. “They have long-range missiles, precision-guided missiles, well-developed cybercapabilities,” she said, all handing Hezbollah the ability to cause “much wider harm to the civilian population” in Israel.
She added, however, that Israel’s newfound unity after months of division over the Netanyahu administration’s moves to weaken Israel’s judiciary would help if Hezbollah attacked.
Despite the high tensions in the region, both Israel and Hezbollah want to avoid an all-out war at this point because each has a lot to lose, according to analysts and former Israeli and Lebanese officials.
Israel, suffering deep trauma from the Hamas attack on Oct. 7 that killed more than 1,400 and saw nearly 200 abducted to Gaza, wants to focus on what Mr. Netanyahu has called Israel’s effort to destroy Hamas.
Hezbollah’s leaders frequently call for the destruction of Israel, but the group has avoided war with the Israelis for more than a decade, suggesting that it prefers to invest its efforts elsewhere.
“I see Hezbollah as more interested in showing layers of power and deterrence against Israel and having a seat at the table at the regional level than in engaging in an all-out conflict,” said Mohanad Hage Ali, the deputy director for research at the Carnegie Middle East Center. “They are more interested in a long-term strategy that brings them more power and influence.”
Firas Maksad, a senior fellow at the Middle East Institute, said a war between Israel and Hezbollah “is going to be increasingly likely, particularly as we approach a ground invasion of Gaza.” But he stressed that if both sides proceeded cautiously, “there is a pathway to avoid that.”
The problem, analysts suggest, is that the more forcefully Israel pursues its goal of attempting to wipe out Hamas, the more pressure there will be on Hezbollah to intervene.
Hezbollah called for protests on Wednesday in the suburbs of southern Beirut, the group’s stronghold, according to Al Manar, the Hezbollah-owned Lebanese broadcaster, after an explosion killed hundreds at a hospital in Gaza City on Tuesday.
Many people had already taken to the streets of Lebanon’s capital on Tuesday evening after the explosion, which the Gazan authorities blamed on an Israeli airstrike and the Israeli military blamed on an errant rocket launched by an armed Palestinian group.
Over the past week, Hezbollah and Israel have launched tit-for-tat attacks across the border, killing relatively small numbers of people on both sides while avoiding greater violence. On Tuesday, the Israeli military said it had targeted fighters attempting to infiltrate Israeli territory, killing some. Hezbollah announced on Tuesday that five of its fighters had been killed, according to the group’s official Al-Manar broadcaster.
For now, Hezbollah is probably seeking to distract the Israeli military from its planned invasion of Gaza by drawing its attention northward, while still avoiding full-blown war, Ms. Mizrahi said.
But the greater the tension, the greater the chances that one side will make a deadly miscalculation, Mr. Maksad said, for example, by striking an unintended target or killing a larger number of enemy forces than planned, putting pressure on the other side to respond.
And some in Israel’s security establishment may believe that now is the time to strike Hezbollah, to ensure that the group can’t take the initiative against Israel, said Sima Shine, a former head of research for Israel’s intelligence agency.
“They say, ‘We made the mistake once with Hamas,’” assuming that the threat the group posed could be managed, she said.
But so far, Mr. Netanyahu has vetoed such proposals, according to American officials and others briefed on the discussions.
For now, both sides appear to be in a waiting game to see how the dynamics of Israel’s expected invasion of Gaza will play out.
General Ibrahim, the former Lebanese security chief, said he believed that Hezbollah’s “red lines” included any Israeli effort to eliminate the Hamas leadership or a Palestinian death toll in the tens of thousands. Israeli officials have already announced their intention to get rid of top Hamas officials, and Gaza officials say the death toll is now more than 2,800.
As the war proceeds and images of Israeli airstrikes destroying Gazan cities and rescuers pulling the dead and wounded from the rubble flood Arabic news channels, calls will most likely increase among Hezbollah supporters for a response.
“The key issue will be the scale of the violence that the Israel occupation army will impose on Gaza and particularly on the structures of Hamas,” said Joseph Daher, the author of a book about Hezbollah.
Ben Hubbard reported from Beirut, Lebanon, and Aaron Boxerman from Jerusalem. Euan Ward contributed reporting from Beirut.