A war in all but name simmers at Israel-Lebanon border

“It’s quieter than usual," said Lt. Col. Dotan Razili of the Israeli army, sheltering from the rain in this rural community 300 yards from the Lebanese border. “It makes me suspicious."

An undeclared war is festering all along the hill country that separates Israel and Lebanon. It involves nearly as many troops as the war in the Gaza Strip. So far it’s a largely static battle of missiles, artillery, bombing raids and stealthy infiltration.

Hezbollah hasn’t unleashed its long-range firepower. Israel hasn’t ordered forward its tanks. But the fighting has intensified this month. Nobody knows how long the border battle can continue before the gloves come off.

“We don’t yet have a name for it," Razili said of the cross-border conflict—but across northern Israel and in southern Lebanon, people are starting to call it a war.

U.S. diplomats are trying, fruitlessly so far, to broker a cease-fire based on Hezbollah pulling back its fighters from Israel’s doorstep. The militant Shia movement has vowed to carry on firing missiles at Israel for as long as Israeli forces are fighting in the Gaza Strip against Hamas, an ally of Hezbollah and its backer Iran.

Washington has urged Israel not to launch a ground assault on southern Lebanon. Such a step would sharply escalate the war in the Middle East that began with Hamas’s bloody Oct. 7 assault on southern Israel and is already sparking exchanges of bombs, missiles and targeted killings from the Levant to the Red Sea to the Persian Gulf.

Hezbollah, caught off guard by events since Oct. 7, is looking to avoid all-out war by restricting its attacks to towns and military bases in a strip across Israel’s north. But Israel says it will have no choice but to drive Hezbollah away from its border unless there’s an unexpected diplomatic breakthrough.

Israelis from apple farmers to army chiefs say the situation in the north is intolerable. The country fears losing a swath of its hard-won livable space. Israel’s defense minister and chief of staff warned in recent days that time is running out.

Israel has evacuated most of the civilians from the border area. Some 120,000 are currently displaced, according to Giora Zaltz, head of the Upper Galilee regional council. “The regional economy is frozen," he said.

Hanita and other northern kibbutzim, close-knit communities founded on socialist ideals last century, have become ghost villages. Residents say they won’t return home as long as Hezbollah fighters are based near the border fence. Those include its feared Radwan Force commandos, who have repeatedly tried to cross the border in small groups since October.

The shock of Oct. 7, when the U.S.-designated terrorist group Hamas massacred some 1,200 people, mostly civilians, has shattered Israelis’ sense of security and made them fear that Hezbollah will copy the attack. Hezbollah’s forces are far better armed and trained than Hamas.

Tens of thousands of Israeli troops are holding defensive positions in these northern woodlands. Hezbollah fighters fire missiles and mortars at them from hiding places in the pine forest.

Almost daily, the militants fire Russian-made Kornet laser-guided missiles with a range of up to 6 miles, designed to penetrate the thickest armor on a tank, but here used against military and civilian targets alike, from vehicles to houses.

The Israelis respond with artillery and airstrikes. Merkava tanks wait under trees. Patient defense doesn’t come easy for Israel’s army.

“We are usually an attacking force, we take the initiative. Defending for 100 days is quite difficult," said Razili. In December a Kornet narrowly missed him. He made a menorah for the Hanukkah holiday out of the rocket’s tail.

The army has dusted off and reprinted an old manual from 1956 on forgotten defensive tactics, such as how platoons should dig foxholes. The divisions in the north are also planning and practicing for an armored thrust into Lebanon. “We are ready for it," said Razili.

As the rain hardened, he stroked a lonely cat by a house in Hanita whose roof had been destroyed by a Kornet. The crump of another missile impact carried from the next kibbutz to the east. Israeli 155mm guns opened up somewhere in the clouded valley. A machine gun rattled in the mist.

Hill-fighting in the winter rains is disorienting for many soldiers, said Razili. “Even experienced people have to retrain their ear to understand how close or far away the sounds are."

Another Israeli invasion of Lebanon could cause massive destruction in both countries. In recent years Hezbollah has built up an arsenal of about 150,000 missiles with help from Iran and Syria. The missiles, with many ranges and degrees of accuracy, can reach any city in Israel, down to the Red Sea port of Eilat. Israel has one of the world’s best missile defense networks, but the sheer size of Hezbollah’s stockpile could swamp it.

“If they fire everything they have, as good as our defense systems are, there will be a lot of casualties," said Eyal Hulata, former head of Israel’s National Security Council.

Israel last invaded southern Lebanon in 2006 after Radwan fighters abducted two Israeli soldiers. Israeli bombardment killed around a thousand Lebanese civilians and pounded civil infrastructure including Beirut’s airport, but did limited damage to Hezbollah.

The militant group emerged politically strengthened, despite facing criticism in Lebanon for provoking the war. Israel won only a United Nations cease-fire resolution that called for Hezbollah to withdraw north. It never did.

Instead, Hezbollah beefed up its armory of weapons from Iran, Syria, Russia and China. Many of its 30,000 full-time soldiers are now battle-hardened from a decade of fighting in Syria’s civil war. “They are much more professional than Hamas," said Razili.

Fear is rising across Lebanon that Israel will further expand its airstrikes. Israeli bombing and shelling has already hit towns and villages in the south, displacing about 100,000 Lebanese civilians so far. Memories of the destruction of 2006 are still fresh.

Munira Eid is one of the few people left in the Lebanese village of Aalma El Chaeb, less than a mile over the border from Hanita. The 67-year-old refused to leave her house, where she lives from food grown in her garden. She misses her four children and her grandchildren, who live in Beirut and can no longer visit. “They are safe at least, but the house is soulless without the family," she said.

On Saturday an Israeli airstrike damaged the church in the predominantly Christian village. Hezbollah fighters have been known to operate from the fields nearby, but not from the village itself, say locals.

“We are living a day-by-day war, but everything seems small compared with what lies ahead," said Eid. She said she feels agony about the escalating fighting and blames Hezbollah for starting it.

“The situation could have been avoided by Hezbollah, but the Israelis are losing their minds. The strikes are worse than 2006," she said.

Hezbollah is stepping up its military preparations for an Israeli incursion that it sees as increasingly likely, according to people familiar with the group’s thinking.

Lebanon’s government says it’s up to Israel to avoid further escalation. Government officials say privately they feel helpless. The fragile Lebanese state has little control over Hezbollah.

Israel was close to launching an offensive against Hezbollah days after Oct. 7. President Biden urged Israeli Prime Minister Benjamin Netanyahu not to. Washington has leverage: Israel needs U.S. weaponry and ammunition, as well as diplomatic protection against worldwide criticism of Israel’s war in Gaza.

Many Israeli policymakers and citizens see Hezbollah as a formidable and growing threat that has to be dealt with.

Even if diplomacy leads to a cease-fire, few people from Israel’s north believe it would make the region safe again. Oct. 7 has changed Israelis’ perceptions.

“All the years they bombed us, but they never came across the fence. When Hamas did it, we got scared that Hezbollah would do it even worse," said Ziv Halperin, a mother of three small children from Kibbutz Baram, on the northern border.

Baram’s 300 residents decided to evacuate the day after Hamas’s slaughter in the south. Halperin and others now live in hotels by the Sea of Galilee, paid for by the government.

“Most of us from the kibbutzim, we’re very left, we’re liberal, we want peace," said Halperin. “We don’t think force is the solution. But after Oct. 7, we think that is their language."

Halperin fears her kibbutz, founded the year after Israel declared independence in 1948, could wither away. As the border war worsens, inhabitants are dispersing, finding housing and schools elsewhere in Israel. “It’s hard to put back together," she said.

“The government has to do what they can to make us feel safe, to get Hezbollah away from the fence, so that what happened in Gaza could never happen here," Halperin said.

She recalled life in Baram fondly, with its views of forested mountains and picturesque Lebanese villages. Recently it gained a view of Hezbollah’s flag, planted yards from the Israeli border post. She fears her family, descendants of the kibbutz’s founders, might have to move on.

On a melancholy morning in Baram, three gray-haired men stood beneath a tarpaulin spanning concrete blocks, a makeshift shelter from the enemy and the rain. They’re members of the kibbutz’s civil defense force against terrorist attack.

Some of their peers in southern Israel were overrun and killed by Hamas on Oct. 7. “This changed the game," said Raviv Gutman, head of Baram’s defense force, bearing an automatic rifle.

Artillery fire sounded from the forest. Baram’s homes and lanes stood silent. At its deserted daycare center, the staffing roster was frozen in time on Oct. 6.

Israel’s firepower is taking a toll on Hezbollah, which says more than 160 of its fighters have been killed. Some 19 Lebanese civilians have also been killed. In Israel, Hezbollah has killed 12 soldiers and at least six civilians so far.

Israeli officers say they have forced Hezbollah to retreat somewhat from the fence. But Radwan fighters periodically cross the border, hunting for soldiers and residents.

Shadi Khalloul stood on a blustery hilltop in the Israeli border town of Jish and pointed to where a small group of Radwan had infiltrated the valley the night before. Israeli jets had hit them, their bombs flashing in the rain, said Khalloul, a Maronite Christian and major in the Israeli reserves.

To his left stood Mount Meron, where Hezbollah damaged an Israeli air surveillance base earlier this month, partly overcoming its defenses by firing more than 60 missiles.

Straight ahead, over the border, lay the mainly Shia village of Yaroun, from where Hezbollah fired a Kornet missile at a school in nearby Kibbutz Sasa last month. The antitank missile made a mess of the school’s newly renovated auditorium. Had the children not already been evacuated, “we would be fighting in Lebanon by now," said Khalloul.

Behind him stood the Maronite Church of Our Lady. Next to it lay the ruined columns of a Roman-era synagogue. In the valley sat the tomb of the biblical prophet Joel.

Israeli forces evicted Khalloul’s grandparents and other Lebanese-Arabic speakers from Baram during Israel’s war of independence in 1948. Still the former career soldier is a proud Israeli, calling it the only safe place for Christians in the Middle East. “You cut my veins, you see Israel there," he said, pointing to his wrist.

“People are angry with the government because nothing is happening," said Khalloul. “We don’t believe that any diplomatic solution will work. Only war will work."

Adam Chamseddine in Beirut contributed to this article.

Write to Marcus Walker at Marcus.Walker@wsj.com