The Israeli army says it has killed a commander of the Imam Hussein division, referring to a Hezbollah-linked group based in Syria, in a strike in Beirut as it stepped up attacks across Lebanon.

Israel also said on Tuesday that its forces killed Hezbollah commander Muhammad Jaafar Qasir, describing him as being responsible for weapons transfers from Iran and its affiliates to the Lebanese armed group Hezbollah.

The announcements came as Iran fired a salvo of ballistic missiles at Israel on Tuesday in what it said was retaliation for the assassinations of Hezbollah, Hamas and Islamic Revolutionary Guard Corps officials. Israel promised a “painful response”, saying that more than 180 missiles were launched into Israel from Iran and Israeli air defences were activated to intercept them.

Iran’s Islamic Revolutionary Guard Corps said Iran had launched tens of missiles at Israel and that if Israel retaliated, Tehran’s response would be “more crushing and ruinous”. Tehran targeted three Israeli military bases in its attack, Iran’s state news agency said.

It comes a day after Israel said it sent ground troops into southern Lebanon in what it described as a “limited” operation against Hezbollah targets.

While Hezbollah denied that Israeli troops had entered Lebanon, the Israeli army announced it had also carried out dozens of ground raids into southern Lebanon going back nearly a year.

Israeli forces have continued to launch attacks on towns and villages across the border as well as on the densely-populated southern Beirut suburbs.

In an attack on Tuesday evening, Israeli air raids struck two areas in Beirut’s Dahiyeh neighbourhood, hitting a building in Jnah near the Zahraa Hospital, and a building near the Kuwaiti embassy, Lebanon’s National News Agency said.

Israel also warned Lebanese people to evacuate border towns as it conducted its ground operation.

Almost 240,000 people, mostly Syrians, have crossed to Syria since Israel began pounding the country last week, Lebanese authorities said.

A report from the country’s disaster management unit has registered “the crossing of 176,080 Syrian citizens and 63,373 Lebanese citizens into Syrian territory” from September 23.

‘My whole life changed in a second’

Iran had promised to retaliate following Israeli strikes that have killed many of the top leaders of its ally Hezbollah in Lebanon, including the group’s leader Hassan Nasrallah.

Hamas, the Palestinian group in Gaza, praised the Iranian missile strikes, saying they avenged the Israeli assassinations of three leaders, including Nasrallah.

In Washington, President Joe Biden said the United States was prepared to help Israel defend itself from Iranian missile attacks.

Writing on X about a meeting held with Vice President Kamala Harris and the White House national security team earlier in the day, Biden said: “We discussed how the United States is prepared to help Israel defend against these attacks, and protect American personnel in the region.”

United Nations Secretary-General Antonio Guterres, condemned what he called “escalation after escalation”, saying: “This must stop. We absolutely need a ceasefire.”

A ground campaign into Lebanon for the first time in 18 years pitting Israeli soldiers against Hezbollah would be a major regional escalation.

Near the city of Sidon along the Mediterranean south of Beirut, mourners wept over coffins containing black-shrouded bodies of people killed in Israeli strikes.

“The building got struck down and I couldn’t protect my daughter or anyone else. Thank God, my son and I got out, but I lost my daughter and wife, I lost my home, I have become homeless. What do you want me to say? My whole life changed in a second,” said resident Abdulhamid Ramadan.

Hezbollah fighters responded to Israeli attacks by firing a barrage of rockets into Israel on Tuesday. There was no immediate word on casualties.

Hezbollah has been reeling from weeks of targeted strikes that killed its leadership. Israeli strikes have killed more than 1,000 people in Lebanon over the past two weeks, nearly a quarter of them women and children, according to the country’s Ministry of Public Health.

Anticipating more rocket attacks from Hezbollah, the Israeli army announced new restrictions on public gatherings and closed beaches in northern and central Israel. The military also said it was calling up thousands more reserve soldiers to serve on the northern border.

Earlier on Tuesday, an Israeli military official said Hezbollah had launched rockets at central Israel, setting off air raid sirens and wounding a man. Hezbollah said it fired salvos of a new kind of medium-range missile at the headquarters of two Israeli intelligence agencies near Tel Aviv.

The Israeli military official said Hezbollah had also launched projectiles at Israeli areas near the border, targeting soldiers.

Haaretz columnist Gideon Levy said Israel, in its two major wars it fought previously inside Lebanon, “always started in a very limited way, very limited scale”.

“I’m very afraid that it will repeat itself now, and that [the situation in] Gaza will happen in Lebanon,” Levy told Al Jazeera. He said Israel is motivated by its recent military successes, such as the assassination of Nasrallah and the explosions of pagers and walkie-talkies in Lebanon.

“The world is totally passive, so Israel feels that it can go on,” Levy warned. “I think nothing is going to stop Israel from going on and this will cost the lives of many people.”