TEL AVIV — The Israeli army chief said Wednesday that the military is preparing for a possible ground operation in Lebanon as Hezbollah hurled dozens of projectiles into Israel, including a missile aimed at Tel Aviv that was the militant group’s deepest strike yet.

Addressing troops on the northern border, Chief of Staff Lt. Gen. Herzi Halevi said the latest Israeli airstrikes were designed to “prepare the ground for your possible entry and to continue degrading Hezbollah.”

In an apparent reference to the missile aimed at Tel Aviv, he said: “Today, Hezbollah expanded its range of fire, and later today, they will receive a very strong response. Prepare yourselves.”

To achieve the goal of returning the displaced citizens of northern Israel to their homes, “we are preparing the process of a maneuver,” he said.

In recent days, the Israeli military has said it had no immediate plans for a ground invasion. Halevi’s statement was the strongest yet from an Israeli leader suggesting that troops could move in.

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Escalating Tensions and Casualties

In other developments, the Lebanese health minister said continued Israeli strikes on Wednesday killed more than 50 people. That raised the death toll from the past three days to 615, with more than 2,000 people wounded.

This week has been the deadliest in Lebanon since the bruising monthlong war between Israel and Hezbollah in 2006. With tensions still escalating, the Israeli military said it would activate reserve troops.

Israeli military officials said they intercepted Hezbollah’s surface-to-surface missile, which marked a further escalation after Israeli strikes on Lebanon killed hundreds of people.

The missile set off air-raid sirens in Tel Aviv and across central Israel. There were no reports of casualties or damage. The military said it struck the site in southern Lebanon where the missile was launched.

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Displacement and Humanitarian Crisis

The launch ratcheted up hostilities as the region appeared to be teetering toward another all-out war, even as Israel continues to battle Hamas in the Gaza Strip. Thousands have fled their homes in parts of Lebanon coming under fire.

Israel said Wendesday its air force had struck some 280 Hezbollah targets across Lebanon by early afternoon, including launchers used to fire rockets on the northern Israeli cities of Safed and Nahariya.

Fleeing families have flocked to Beirut and the coastal city of Sidon, sleeping in schools turned into shelters, as well as in cars, parks and along the beach. Some sought to leave the country, causing a traffic jam at the border with Syria.

The United Nations said more than 90,000 people have been displaced by five days of Israeli strikes on Lebanon. The U.N. Office for the Coordination of Humanitarian Affairs said Wednesday that a total of 200,000 people have been displaced in Lebanon since Hezbollah began firing rockets into northern Israel nearly a year ago, drawing Israeli retaliation.

Hezbollah said it fired a Qader 1 ballistic missile targeting the headquarters of Israel’s Mossad intelligence agency, which it blames for a recent string of targeted killings of its top commanders and for an attack last week in which explosives hidden in pagers and walkie-talkies killed dozens of people and wounded thousands, including many Hezbollah members.

The Israeli military said it was the first time a projectile fired from Lebanon had reached central Israel. Hezbollah claimed to have targeted an intelligence base near Tel Aviv last month in an aerial attack, but there was no confirmation. The Palestinian Hamas militant group in Gaza repeatedly targeted Tel Aviv in the opening months of the war.

The announcement about reserve troops indicated Israel is planning even tougher action against Hezbollah. The army said it would call up two reserve brigades for missions in the north.

“This will enable the continuation of combat against the Hezbollah terrorist organization,” the military said.

Hezbollah’s latest strikes included dozens of rockets fired Wednesday into northern Israel, the military said. Two people suffered shrapnel wounds, according to Israel’s Magen David Adom rescue service.

Israel responded with its own new strikes on Hezbollah. In Lebanon, at least three people were killed and nine wounded in an Israeli strike near Byblos, according to the country’s Health Ministry. The coastal town is north of Beirut and far from Hezbollah’s main strongholds.

Tensions between Israel and the Lebanese militant group have steadily escalated over the last 11 months. Hezbollah has been firing rockets, missiles and drones into northern Israel in solidarity with Palestinians in Gaza and its ally Hamas, a fellow Iran-backed militant group.

Israel has responded with increasingly heavy airstrikes and the targeted killing of Hezbollah commanders while threatening a wider operation.

The U.N. Security Council scheduled an emergency meeting on Lebanon for Wednesday at the request of France.

Nearly a year of fighting between Hezbollah and Israel had already displaced tens of thousands of people on both sides of the border before the recent escalation. Israel has vowed to do whatever it takes to ensure its citizens can return to their homes in the north, while Hezbollah has said it will keep up its rocket attacks until there is a cease-fire in Gaza, something that appears increasingly remote.

The rocket fire over the past week has disrupted life for more than 1 million people across northern Israel, with schools closed and restrictions on public gatherings. Many restaurants and other businesses are shut in the coastal city of Haifa, and there are fewer people on the streets. Some who fled south from communities near the border are coming under rocket fire again.

Israel has moved thousands of troops who had been serving in Gaza to the northern border. It says Hezbollah has some 150,000 rockets and missiles, including some capable of striking anywhere in Israel, and that the group has fired some 9,000 rockets and drones since last October.

Lt. Col. Nadav Shoshani, an Israeli military spokesperson, said the missile fired Wednesday had a “heavy warhead” but declined to elaborate or confirm it was the type described by Hezbollah. He dismissed Hezbollah’s claim of targeting the Mossad headquarters, located just north of Tel Aviv, as “psychological warfare.”

The Iranian-made Qader is a medium-range surface-to-surface ballistic missile with multiple types and payloads. It can carry an explosive payload of up to 800 kilograms (1,760 pounds), according to the Washington-based Center for Strategic and International Studies. Iranian officials have described the liquid-fueled missile as having a range of 2,000 kilometers (1,240 miles).

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Cross-border fire began ramping up Sunday after the pager and walkie-talkie bombings, which killed 39 people and wounded nearly 3,000, many of them civilians. Lebanon blamed Israel, but Israel did not confirm or deny responsibility.

The next day, Israel said its warplanes struck 1,600 Hezbollah targets, destroying cruise missiles, long- and short-range rockets and attack drones, including weapons concealed in private homes. The strikes racked up the highest one-day death toll in Lebanon since Israel and Hezbollah fought a bruising monthlong war in 2006.

An Israeli airstrike in Beirut Tuesday killed Ibrahim Kobeisi, whom Israel described as a top Hezbollah rocket and missile unit commander. Military officials said Kobeisi was responsible for launches toward Israel and planned a 2000 attack in which three Israeli soldiers were kidnapped and killed. Hezbollah later confirmed his death.

It was the latest in a string of assassinations and other setbacks for Hezbollah, which is Lebanon’s strongest political and military actor and is widely considered the top paramilitary force in the Arab world.