Israel-Gaza-Lebanon updates: Beirut pummeled by 30 overnight strikes

Secretary of State Antony Blinken said Monday that slain Hezbollah leader Hassan Nasrallah was "a brutal terrorist, whose many victims included Americans, Israelis, civilians in Lebanon, civilians in Syria and many others as well."

During a ministerial meeting on defeating ISIS in Washington, D.C., Blinken said Hezbollah under Nasrallah's leadership "terrorized people across the region and prevented Lebanon from fully moving forward as a country."

"Lebanon, the region, the world, are safer without him," Blinken added.

Nasrallah was killed in an Israeli airstrike in southern Beirut on Friday, marking the most significant blow yet to Hezbollah over almost a year of cross-border conflict with Israel.

Israeli airstrikes are continuing across Lebanon and in the capital. A U.S. official told ABC News on Sunday that small-scale cross-border Israeli ground operations may have already begun, as a prelude to a wider offensive into southern Lebanon in pursuit of Hezbollah targets.

Blinken said the U.S. and its partners would continue to work toward a diplomatic solution "that provides real security to Israel, to Lebanon, and allows citizens on both sides of the border to return to their homes."

"Diplomacy remains the best and only path to achieving greater stability in the Middle East," he said. "The United States remains committed to urgently driving these efforts forward."

-ABC News' Shannon K. Kingston

Israeli Prime Minister Benjamin Netanyahu appealed to anti-government sentiment in Iran on Monday, telling the Iranian people: "With every passing moment, the regime is bringing you -- the noble Persian people -- closer to the abyss."

"Every day, you see a regime that subjugates you make fiery speeches about defending Lebanon, defending Gaza," the prime minister said in a video statement posted to social media.

"Yet every day, that regime plunges our region deeper into darkness and deeper into war. Every day, their puppets are eliminated."

"Ask Mohammed Deif. Ask [Hassan] Nasrallah," Netanyahu said, referring to the Hamas military commander -- whose death the group has not confirmed -- and the former Hezbollah leader. Israel claims Deif was killed in Gaza in July, while Nasrallah was killed in Beirut on Friday.

"There is nowhere in the Middle East Israel cannot reach," Netanyahu said.

"Iran's tyrants don't care about your future," Netanyahu continued. "When Iran is finally free -- and that moment will come a lot sooner than people think -- everything will be different."

"Our two ancient peoples, the Jewish people and the Persian people, will finally be at peace," Netanyahu said. "The people of Iran should know -- Israel stands with you."

Tehran has not yet responded to Netanyahu's statement. But on Monday, the Iranian Foreign Ministry spokesperson said his country would not deploy volunteer troops to Lebanon in response to Israel's expanding campaign there against Hezbollah.

"We believe that the governments and nations of the region have the necessary ability and authority to defend themselves," he said. "We have not had any request from anyone, and we know that they do not need deployment of human forces from our side."

-ABC News' Joe Simonetti and Somayeh Malekian

The Israel Defense Forces said Monday it killed Fatah Sharif Abu al-Amine, the head of Hamas' Lebanon branch, in an overnight airstrike.

"Sharif was responsible for coordinating Hamas' terror activities in Lebanon with Hezbollah operatives," the IDF said in a statement.

"He was also responsible for Hamas' efforts in Lebanon to recruit operatives and acquire weapons."

-ABC News' Jordana Miller and Joe Simonetti

An overnight precision strike on an apartment building in the Cola neighborhood was the first such strike in central Beirut for 18 years.

Four people were killed, including three members of the Popular Front for the Liberation of Palestine militant group.

Israel did not immediately claim the strike but is widely assumed to have carried it out.

-ABC News' Joe Simonetti