BEIRUT — The Palestinian militant group Hamas said an Israeli airstrike killed its leader in Lebanon in the city of Tyre on Monday, and another Palestinian organization said three of its leaders died in a strike in central Beirut – the first such hit inside the capital’s limits.

The killings were the latest in a two-week wave of intensified Israeli attacks on militant targets in Lebanon, part of a conflict also stretching from the Palestinian territories of Gaza and the occupied West Bank, to Yemen, and within Israel itself.

Lebanon’s Hezbollah said it is ready for any Israeli land invasion in Lebanon.

Israel’s intensified attacks against the Iran-backed Hezbollah and Houthi forces in Yemen have prompted fears that Middle East fighting could spin out of control and draw in Iran and the United States, Israel’s main ally.

Hamas said its leader in Lebanon, Fateh Sherif Abu el-Amin was killed along with his wife, son and daughter, in a strike that targeted their house in a refugee camp in the southern city of Tyre in the early hours of Monday.

Another group, the Popular Front for the Liberation of Palestine (PFLP), said three of its leaders were killed in a strike that targeted Beirut’s Kola district.

This was the first time Israel had struck Beirut beyond its southern suburbs in a campaign which culminated in the assassination of Hezbollah’s veteran leader Hassan Nasrallah last week in a succession of heavy air strikes.

The strike against the PFLP hit the upper floor of an apartment building, Reuters witnesses said. There was no immediate comment from the Israeli military.

The latest attacks indicated Israel has no intention of slowing down its offensive on multiple fronts even after eliminating Nasrallah, who was Iran’s most powerful ally in its “Axis of Resistance” against Israeli and US influence in the region.

Iranian Foreign Ministry spokesperson Nasser Kanaani said Tehran would not leave any of Israel’s “criminal acts” go unanswered. He was referring to the killing of Nasrallah and an Iranian Guard deputy commander, Brigadier General Abbas Nilforoushan, who died in the same strikes on Friday.

Lebanon’s Health Ministry says more than 1,000 Lebanese have been killed and 6,000 wounded in the past two weeks, without specifying how many were civilians. One million people – a fifth of the population – have fled their homes, the government says.

HOUTHIS HIT

The escalation has put Beirut on edge, with Lebanese fearful that Israel will expand its military campaign.

“There is nothing else to say or add, except God save Lebanon,” Beirut resident Nawel said. “What will happen to me is the same as what can happen to anyone.”

More than 100,000 people have crossed into Syria from Lebanon – including nationals of both countries – since the conflict between Israeli forces and Hezbollah escalated this month, U.N. refugee agency chief Filippo Grandi said on Monday.

On Sunday, Israel carried out airstrikes on dozens of Hezbollah targets throughout Lebanon and against the Iran-aligned Houthi militia in Yemen.

The death toll across Lebanon on Sunday rose to 105, health ministry statements showed.

The Houthi-run health ministry in Yemen said at least four people were killed in airstrikes on the port of Hodeidah, which Israel said were a response to Houthi missile attacks.

Israeli drones hovered over Beirut for much of Sunday, with the loud blasts of new airstrikes echoing around the Lebanese capital.

Many of Israel’s attacks have been carried out in the south of Lebanon, where Hezbollah has most of its operations, or Beirut’s southern suburbs. Monday’s attack in the Kola district appeared to be the first strike within Beirut’s city limits.

Israel has vowed to keep up the assault and says it wants to make its northern areas secure again for residents who have been forced to flee Hezbollah rocket attacks.

Exchanges of fire across the Lebanon-Israel border have been taking place almost daily since the war between Hamas and Israel erupted nearly a year ago. Hezbollah has said it was acting in solidarity with Hamas.

The United States, Israel’s close ally, has urged a diplomatic resolution to the conflict in Lebanon but has also authorized its military to reinforce in the region.

U.S. President Joe Biden, asked if an all-out war in the Middle East could be avoided, said: “It has to be.”

He said he would be talking to Israeli Prime Minister Benjamin Netanyahu.

HEZBOLLAH READY

Hezbollah fighters are primed to confront any Israeli ground invasion of Lebanon, the group’s deputy leader Naim Qassem said on Monday in his first public speech since Israeli airstrikes killed its veteran chief Hassan Nasrallah last week.

Israel will not achieve its goals, he said.

“We will face any possibility and we are ready if the Israelis decide to enter by land and the resistance forces are ready for a ground engagement,” he said in an address from an undisclosed location.

He was speaking as Israeli airstrikes on targets in Beirut and elsewhere in Lebanon continued, extending a two-week long wave of attacks that has eliminated several Hezbollah commanders but also killed about 1,000 Lebanese and forced one million to flee their homes, according to the Lebanese government.

Nasrallah’s killing, along with the series of blows against the organization’s communications devices and assassination of other senior commanders, constitute the biggest blow to the organization since Iran created it in 1982 to fight Israel.

He had built it up into Lebanon’s most powerful military and political force, with wide sway across the Middle East.

Now Hezbollah faces the challenge of replacing a charismatic, towering leader who was a hero to supporters because he stood up to Israel even though the West branded him a terrorist mastermind.

“We will choose a secretary-general for the party at the earliest opportunity…and we will fill the leadership and positions on a permanent basis,” Qassem said.

Qassem said Hezbollah’s fighters had continued to fire rockets as deep as 150 km (93 miles) into Israeli territory and were ready to face any possible Israeli ground incursion.

“What we are doing is the bare minimum…We know that the battle may be long,” he said. “We will win as we won in the liberation of 2006 in the face of the Israeli enemy,” he added, referring to the last big conflict between the two foes.

Lebanon’s caretaker Prime Minister Najib Mikati said on Monday his government was ready to fully implement a UN resolution that had aimed to end Hezbollah’s armed presence south of the Litani River as part of an agreement to stop the war with Israel.

Mikati said the Lebanese army could deploy south of the river, which lies about 30 km from the country’s southern border.