Israel-Gaza live updates: Sirens sound in Tel Aviv as Hamas fires rocket from Gaza

At least three people were killed overnight in southern Lebanon, the Lebanese Ministry of Public Health said Sunday.

Two were killed in the village of At Tiri and one in the town of Khiam, the ministry said, adding that two additional people were injured and required hospitalization.

The United Nations agency in charge of peacekeeping in southern Lebanon called on Sunday for a cease-fire and for all sides to "refrain from further escalatory action."

"In light of worrying developments across the Blue Line since the early morning, UNSCOL and UNIFIL call on all to cease fire and refrain from further escalatory action," the agency said in a statement, referring to a demarcation line separating Israel from Lebanon.

There have been no reports of injuries on the Israeli side, according to emergency services in Israel.

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The Israel Defense Forces on Sunday said the military was targeting Hezbollah with additional strikes in southern Lebanon.

"In the last hour, the IDF struck Hezbollah launchers in several areas in southern Lebanon to remove threats," the IDF said in a statement. "In addition, the IDF identified a terrorist cell operating in the area of Khiam in southern Lebanon. The IAF swiftly struck the terrorists."

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Israeli Prime Minister Benjamin Netanyahu on Sunday described his country's preemptive strikes within Lebanon as a "strong action to foil the threats" raised by a potential attack by Hezbollah.

"It has eliminated thousands of rockets that were aimed at northern Israel," Netanyahu said as he convened his Security Cabinet for a meeting at 7 a.m. local time. "It is thwarting many other threats and is taking very strong action -- both defensively and offensively."

Netanyahu had earlier in the morning been managing the situation with Defense Minister Yoav Gallant from the Kirya military base in Tel Aviv, his office said. The prime minister's office released photos of the pair meeting with military officials.

"We are determined to do everything to defend our country, to return the residents of the north securely to their homes and to continue upholding a simple rule: Whoever harms us -- we will harm them," Netanyahu said.

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The Israel Defense Forces on Sunday said it had destroyed "thousands" of Hezbollah rocket launchers.

"Approximately 100 IAF fighter jets, directed by IDF intelligence, struck and destroyed thousands of Hezbollah rocket launcher barrels that were located and embedded in southern Lebanon," the military said in a statement.

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Hezbollah fires rockets at Israel after IDF launches preemptive strike

The Biden administration said it was concerned the attacks would "derail any hopes of a cease-fire with Hamas."

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The statement added, "Most of these launchers were aimed toward northern Israel and some were aimed toward central Israel. More than 40 launches areas in Lebanon were struck during the strikes."

-ABC News' Will Gretsky and Kevin Shalvey