In a sharp escalation of the conflict in the Middle East, Iran launched a massive missile attack with as many as 100 projectiles on Israel Tuesday, media reports said.

The attack came amid Israeli strikes on Lebanon to target Hezbollah, which saw the execution of the militant outfit's commander Hassan Nasrallah, and a top official from Iran's Islamic Revolutionary Guard Corps.

According to the Israeli foreign ministry, the missiles were fired around 10 PM IST.

An hour later, around 11.10 pm, the Israel Defence Forces (IDF) said there was no more threat from Iran "for now".

The civilians were allowed to leave bomb shelters, adding that there were a few "hits" during the barrage.

Confirming the attack, Iran's Revolutionary Guards said it was in response to the killing of Nasrallah, Hamas political chief Ismail Haniyeh, and its senior commander Abbas Nilforoushan, said reports.

The Revolutionary Guards also threatened to carry out "crushing attacks" against Israel if it retaliated.

"If the Zionist regime reacts to Iranian operations, it will face crushing attacks," the Islamic Revolutionary Guard Corps said in a statement carried by the Iranian news agency Fars, according to news agency AFP.

Iran-backed Iraqi armed forces said US bases in Iraq and the region would be targeted if the United States helped Israel in retaliation or if Israel used Iraqi airspace against Tehran, news agency Reuters reported.

Despited warnings, Israel has vowed to retaliate, with IDF spokesman Rear Admiral Daniel Hagari saying the country would respond at the time and place of its choosing.

"This attack will have consequences. We have plans, and we will operate at the place and time we decide," he said.

Meanwhile, amidst the attack, US President Joe Biden ordered the country's military to "aid Israel's defence" and shoot down Iranian missiles targeting its ally.

A White House statement said Biden and Vice President Kamala Harris, who is the Democratic nominee in next month's US presidential election, were both monitoring Iran's attack on Israel from the White House situation room. The agency said some missiles had also been intercepted by neighbouring Jordan.

Videos showed debris from missiles intercepted by Israel's famed Iron Dome and Arrow defence systems raining down on Tel Aviv. The Israeli Defence Forces also confirmed that blasts had been heard in "Jerusalem and elsewhere".

Air traffic was halted at Israel's Ben Gurion airport and the country closed its airspace and diverted flights, a spokesman from the airport authority was quoted as saying in media reports,

The aviation authorities in Jordan and Iraq also announced the suspension of air traffic.