Israel renewed its strikes on Beirut on Thursday, as it threatened to seize territory in Lebanon if Hezbollah did not stop its attacks.

The Israeli military announced "a wave of strikes targeting Hezbollah terrorist infrastructure across Beirut", with AFPTV footage showing dark smoke rising into the sky above two districts in the heart of Beirut.

Israeli Prime Minister Benjamin Netanyahu said Thursday that he had warned Lebanon's government that Israel would act to disarm Hezbollah "on the ground" if Beirut failed to do so.

"I told the Lebanese government a few days ago: you are playing with fire if you continue allowing Hezbollah to operate, in violation of your commitment to disarm it," Netanyahu told a press conference.

U.S. President Donald Trump on Thursday said that stopping Iran from getting nuclear weapons was more important to him than controlling oil prices.

An Israeli strike on a campus of Lebanon's public university killed two academics.

The director of the faculty of sciences at the south Beirut campus of the Lebanese University, Hussein Bazzi, and professor Mortada Srour were killed by an Israeli drone strike on the university, the National News Agency said.

Missiles hit a building in the Beirut neighborhood of Bashoura, near the center of the city, on Thursday, after the Israeli military issued a warning of an incoming strike.

An AFPTV live broadcast showed dark smoke rising into the sky above the heart of the Lebanese capital, and an apparent fire started by the first missile impact.

Iran's new supreme leader Mojtaba Khamenei thanked Tehran's allied armed groups across the region including in Lebanon, Iraq and Yemen on Thursday.

"I also express my sincere gratitude to the fighters of the 'Resistance Front'," Khamenei said in a statement read by a news anchor on state television, referring to the Houthis in Yemen, Lebanon's Hezbollah as well as allied groups in Iraq.

When an air strike hit their Beirut neighborhood, people were angry with Israel, but they reserved their deepest rage for Hezbollah, for dragging Lebanon into the Middle East war.

Israel and the United States launched huge strikes on Iran on February 28, killing its supreme leader and sparking a massive retaliatory campaign.

Turkey's Foreign Minister Hakan Fidan called Thursday for an end to Israel's bombardment of neighboring Lebanon "before it collapses".

"Israel, pursuing expansionist policies, is bringing its dirty war into Lebanon.. Israeli attacks must end before the Lebanese state collapses," he said at a joint news conference in Ankara with his visiting German counterpart Johann Wadephul.

Israeli strikes targeted Thursday several towns in south Lebanon including Haris, Kafra, Alma al-Shaab-Naqoura, Deir Ntar, Barish, Yater, Qantara, Qaaqaiyyet al-Jesser, Teffahta, Qana, al-Sultanieh, Taybeh, Qabrikha and Kfardounin.

In east Lebanon, Israeli strikes targeted Qsarnaba and Douris after warning residents to evacuate.

Israeli Defense Minister Israel Katz said Thursday that he had ordered the military to prepare for expanding operations in Lebanon.

"The Prime Minister and I have instructed the IDF to prepare for expanding IDF operations in Lebanon and for restoring quiet and security to the northern communities," Katz was quoted as saying in a statement.