The alert came after Iranian media reported that Iran's Revolutionary Guards had carried out a joint missile operation with Tehran's Lebanese ally Hezbollah.

The Israeli military urged people in affected areas to head to shelters, as it said it "identified missiles launched from Iran toward the territory of the State of Israel".

"Defensive systems are operating to intercept the threat," the military said on its official Telegram channel.

It later added that it was in turn carrying out "wide-scale" strikes on Tehran and a Hezbollah stronghold in Lebanon's capital.

"The IDF struck 10 terror structures in the Dahieh area (of south Beirut) within 30 minutes, including intelligence headquarters, a headquarters of the Radwan unit, and additional command centres," the military said in a separate post on Telegram.

Sirens sounded across Israel, including in Jerusalem according to AFP correspondents.

The Magen David Adom emergency services said that there were no reported casualties following the missile fire, although paramedics were deployed to treat individuals who fell over on the way to shelters.

The Israeli military later said people could leave emergency shelters.