The Israeli military said on Tuesday that missiles had been launched from Iran towards Israel, and that its home front command had provided life-saving guidelines to people in various parts of the country.
Earlier, the military had announced that any ballistic missile strike from Iran was expected to be widespread and told the public to shelter in safe rooms in the event of an attack.
The Israeli army also said Israel's airspace was closed following the Iranian attack.
The firing of missiles came after Israeli troops launched ground raids into Lebanon, in the biggest escalation of regional warfare since fighting erupted in Gaza a year ago.
Iran has vowed to retaliate following attacks that killed the top leadership of its Hezbollah allies in Lebanon.
Iran's Revolutionary Guards said the country had launched tens of missiles at Israel, and that if Israel retaliated, Tehran's response would be more crushing.
In Washington, President Joe Biden said the United States was prepared to help Israel defend itself.
Meanwhile, four people were killed and seven wounded in a shooting attack in the Jaffa neighbourhood of Tel Aviv on Tuesday. Israeli police said the two shooters had been "neutralised" and the situation was under control.
A United Nations Commission of Inquiry concluded on Tuesday that Israel has committed genocide in Gaza and that top Israeli officials including Prime Minister Benjamin Netanyahu had incited these acts.
Qatar and the United States are on the verge of finalising an enhanced defence cooperation agreement, top US diplomat Marco Rubio said on Tuesday, after Israel's attack on Hamas political leaders in Doha last week drew widespread condemnation.
Israel unleashed a long-threatened ground assault on Gaza City on Tuesday, declaring "Gaza is burning" as Palestinians there described the most intense bombardment they had faced in two years of war.
US President Donald Trump sued the New York Times, four of its reporters, and publisher Penguin Random House for at least $15 billion on Monday, claiming defamation and libel, and citing reputational damage, a Florida court filing showed.
Australia urged social media platforms on Tuesday to employ "minimally invasive" methods to check the age of users covered by its world-first teen social media ban, which take into account artificial intelligence (AI) and behavioural data.