Iran has vowed to retaliate following attacks that killed the top leadership of its Hezbollah allies in Lebanon.
The firing of missiles came after Israel said its troops had launched ground raids into Lebanon, though it described the forays as limited. The Israeli campaign in Lebanon is the biggest escalation of regional warfare since fighting erupted in Gaza a year ago.
In Washington, US President Joe Biden said the United States was prepared to help Israel defend itself from Iranian missile attacks.
"We discussed how the United States is prepared to help Israel defend against these attacks, and protect American personnel in the region," Biden said on X about a meeting held with Vice President Kamala Harris and the White House national security team earlier in the day.
The Iranian missile launches came after Israeli ground troops launched raids into Lebanon and its warplanes bombed from the skies.
RAPID ESCALATION
Though so far characterised by Israel as limited, the first ground campaign into Lebanon for 18 years would pit Israeli soldiers against Hezbollah, Iran's best-armed proxy force in the Middle East.
It marks the biggest escalation of regional warfare since fighting erupted in Gaza a year ago, and follows weeks of intense airstrikes that have decapitated Hezbollah by killing most of its top leaders. More than a thousand Lebanese have been killed and a million have fled their homes.
Iran, which sponsors Hezbollah, has vowed to retaliate against Israel, raising fears that war could spill across borders throughout the region, despite efforts by the United States, Israel's closest and most powerful ally, to contain it.
In the latest announced killing of a senior Hezbollah figure, Israel said it had assassinated Muhammad Jaafar Qasir, describing him as a commander in charge of weapons transfers from Iran and its affiliates.
The rapid escalation that has engulfed Lebanon into war has killed hundreds. 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.
Many Lebanese said they were ready to resist Israeli forces.
"Not just Hezbollah, all of Lebanon will fight this time. All of Lebanon is determined to fight Israel for the massacres it committed in Gaza and Lebanon," said Abu Alaa, a Sidon resident.