Cairo ―Israel said Wednesday it was readying troops for a potential ground incursion into Lebanon, telling soldiers to prepare to “enter enemy territory” as it called up more reservists and sent world leaders scrambling to prevent a full-scale war with Hezbollah militants.

“We are preparing the process of a maneuver,” the Israeli military chief, Lt. Gen. Herzi Halevi, told troops at an exercise along the northern border, “which means your military boots ... will enter enemy territory.”

“You will go in, destroy the enemy there and decisively destroy their infrastructure,” he said, adding that the operation would allow Israeli residents, displaced for months by Hezbollah rocket fire, to “safely” return home.

The remarks came as the Israel Defense Forces announced it was mobilizing two reserve brigades for operations in the north, a move the military said would allow for “the continuation of combat” against Hezbollah, which also fired a rocket, missiles and drones at Israeli communities.

Early Wednesday, the group, which is both a military and political movement, said it launched a ballistic missile toward Tel Aviv, Israel’s commercial and financial center. The target was the headquarters of Israel’s Mossad intelligence agency, according to a Hezbollah statement.

IDF spokesman Nadav Shoshani described the missile, which was intercepted, as “long-range” and said it was the first time Hezbollah had fired a rocket or missile at the city, which is about 70 miles from the Lebanese border.

In remarks to CNN, John Kirby, White House National Security Council spokesman, called the launch “deeply concerning,” as U.S. officials insisted a diplomatic solution was in reach.

“We’re working to prevent escalation, we’re working to make sure this doesn’t get into a full-scale war,” Secretary of State Antony Blinken said on “Good Morning America” on Wednesday. President Joe Biden also told ABC’s “The View” that “an all-out war is possible” but said a comprehensive agreement to halt the fighting in both Lebanon and Gaza was still attainable.

In Lebanon, on day three of what Israel has dubbed “Operation Northern Arrows,” the IDF said its air force attacked more than 280 targets tied to Hezbollah. The attacks killed 72 people, according to the Lebanese Health Ministry, bringing the total death toll to more than 600 since intensive Israeli strikes began earlier this week.

Residents of the capital, Beirut, flocked to grocery stores to stock up on essentials, and thousands of displaced sought shelter in the city. Others attempted to flee to Syria, according to the U.N. refugee agency, which reported hundreds of vehicles backed up at the Syrian border, while some reached the area by foot. “The Middle East cannot afford a new displacement crisis,” said U.N. High Commissioner for Refugees Filippo Grandi.

For nearly a year, Israel and Hezbollah have traded cross-border fire, after the group began lobbing rockets to protest the Gaza war. But the strikes on both sides were largely confined, even as thousands of people - including 110,000 in southern Lebanon and 63,500 in northern Israel - were displaced over the months.

The conflict escalated dramatically last week, however, when thousands of pagers and walkie-talkies carried by Hezbollah members exploded simultaneously, an attack for which U.S. officials have acknowledged Israel was responsible. On Friday, the Israeli military assassinated a top commander in an airstrike near Beirut, killing at least 45 people, Lebanese health officials said.

Pope Francis weighed in on Wednesday, saying he was “saddened” by the news of “bombings, death, and destruction” in Lebanon. “May the international community make every effort to stop this terrible escalation. It is unacceptable,” he said in a statement on X.

But even as diplomats and world leaders implored the sides to de-escalate, Israeli officials signaled Wednesday they planned to press forward with the offensive, which they hope will push Hezbollah forces out of southern Lebanon.

“We are delivering blows to Hezbollah that they could not have imagined,” Israeli Prime Minister Benjamin Netanyahu said in a recorded message. “We are doing this with strength, we are doing this with cunning,” he said, adding that Israel “will not rest” until residents can return home in the north.

Israel’s move to call up more reserve brigades was one of the clearest signs the war could expand. The military did not say what type of troops were mobilized, but reserve brigades can be ready for action “in less than 24 hours,” according to Ariel Heimann, a senior researcher at the Institute for National Security Studies in Tel Aviv and former chief reserve officer for the IDF.

The two brigades mobilized Wednesday, which would include several thousand soldiers, could be deployed “for the operation itself in Lebanon, as a backup and readiness force for such an operation, or as a force to replace other units currently stationed on the border, allowing them to go on the mission,” he said.

The problem, according to Heimann, is that the Israeli government doesn’t appear to have an exit plan, with previous - and deadly - forays into Lebanon hanging over the military. Israel invaded in 1982 and formally occupied southern Lebanon until 2000. Hezbollah, which originated as a force to fight foreign powers in the country, took credit for Israel’s withdrawal.

“Israel cannot afford a very long war, both in terms of the resilience of Israeli society, which has already endured several blows, and in terms of military capability - the army has been ‘stretched’ for a year - and also from an economic perspective,” Heimann said.

Israeli forces are also still operating in Gaza, where Netanyahu has pledged to indefinitely occupy the enclave’s border with Egypt. After a short lull, Israeli strikes there appeared to pick up, with at least 66 people killed over the last two days, according to Mahmoud Bassal, spokesman for Gaza’s civil defense force.

“The military and the public have an interest in ending this as quickly as possible,” Heimann said of the Lebanon operation.

After three days of strikes, and the mass pager and radio attacks last week, Lebanon’s health-care system and other infrastructure are already buckling, relief workers said. Years of economic turmoil meant hospitals, clinics and rescue workers were short on supplies before the latest escalation, while many had struggled to make ends meet.

Israeli airstrikes in the south and the Bekaa Valley in the east have damaged water infrastructure, cutting off access to clean water for at least 30,000 people, the United Nations said.

Some of the wounded now reaching hospitals cannot pay for their treatment, according to Zeina Zouein, deputy director of programs for the International Rescue Committee in Lebanon, leaving the cash-strapped Lebanese government to absorb the cost. Others in southern Lebanon, including the elderly, don’t have enough money to flee and are stuck in dangerous areas.

Because of heavy Israeli bombardment, emergency teams often can’t reach the wounded or bring them back promptly, said Maurizio Campailla, head of mission in Lebanon for Doctors Without Borders. Two of the organization’s clinics have closed since Monday because staff could not access them safely, he said.

For months, “we have been preparing ourselves for the war and now all of a sudden, the war arrived,” he said.

Israel on Wednesday expanded its strikes, hitting buildings for the first time in the town of Maaysra, more than 20 miles north of Beirut. Videos verified by The Washington Post showed plumes of smoke rising in the area, and Lebanon’s civil defense force said it retrieved seven bodies from the scene.

Strikes outside Hezbollah’s traditional strongholds, including southern Lebanon and suburbs south of Beirut, are “a warning ... that the entire country is a potential conflict theater for [Israel],” said Amal Saad, a Hezbollah specialist and lecturer at Cardiff University.

But ramping up targets could lead to “an all-out war - a war without ceilings, which means no rules of engagement, everywhere is fair game, everything is a target,” Saad said.

“Hezbollah’s intentions are to prevent that from happening” because of the damage it would do to Lebanon, she said. But Israel’s air campaign alone probably won’t convince the group to capitulate and pull back from the border, she said.

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Soroka reported from Tel Aviv and Haidamous from Beirut. Mohamad El Chamaa and Kareem Fahim in Beirut, Yasmeen Abutaleb in Washington and Hajar Harb and Adela Suliman in London contributed to this report.