Millions of Israelis are under fire after Iran launched at least 100 missiles at Israel, according to the IDF.

Videos showing missiles raining down over the skies of Jerusalem were shared online as warning sirens blanketed central Israel as the IDF said they might be set off by a “variety of threats”.

A statement issued by the IDF said: “A short time ago, missiles were launched from Iran towards the State of Israel. You are asked to remain vigilant and follow the Home Front Command's instructions precisely.”

The Israeli military said they were doing: “Everything necessary to protect the civilians of Israel. The IDF is fully prepared for both defence and offense at peak readiness.”

The statement added, “The air defence system is fully operational, detecting and intercepting threats wherever necessary, even at this moment. However, the defence is not hermetic, and therefore it is essential to follow the Home Front Command's instructions. You may hear explosions, which could be the result of interceptions or impacts.

"Continue to act responsibly and keep calm, as you have done so far, and make sure to follow the guidelines. We are strong and can handle this event as well.

“The IDF is doing and will continue to do everything necessary to protect the civilians of Israel. The IDF is fully prepared for both defence and offense at peak readiness.”

All commercial flights currently on the way to Israel are being rerouted.

Earlier today, the US said it was ready to take all measures to assist Israel in intercepting any threats from Iran.

Streaks of fire over Israeli skies (Credit: Getty)

A senior White House official announced that they had received indications on Tuesday that Iran was planning the attack.

“We are actively supporting defensive preparations to defend Israel against this attack. A direct military attack from Iran against Israel will carry severe consequences for Iran,” the spokesperson said.

In April, the United States, the United Kingdom and Israel jointly intercepted a series of drones and missiles launched at Israel, together with partners including Saudia Arabia and Jordan.