AFP

Israel's massive strikes on Iran, which it calls an existential threat, have hit nuclear and military facilities, killed top commanders and dozens of civilians, and sought to destroy the country's defence capabilities.

Iran called the Israeli air assault "a declaration of war" and fired dozens of missiles at Israel later Friday and Saturday.

"Everything happened in front of me, and even I couldn't believe how I managed to come out alive from that," British citizen Vishwash Kumar Ramesh said from his hospital bed on Friday, speaking in Hindi to national broadcaster DD News.

Jordan and Iraq on Friday announced the closure of their airspace and grounded all flights after Israel's attack on Iran, with Amman vowing it would not allow any violations of its airspace.

Oil prices soared more than 12 percent and stocks sank Friday after Israel launched strikes on Iranian nuclear and military sites and warned of more to come, stoking fears of a full-blown war.

Israel pounded Iran in a series of air raids on Friday, striking 100 targets including Tehran's nuclear and military sites, and killing the armed forces' chief of staff, the head of Iran's Revolutionary Guards and top nuclear scientists.

Iran's Revolutionary Guards chief Hossein Salami, who was killed in an Israeli air strike on Tehran Friday, was a veteran officer close to supreme leader Ayatollah Ali Khamenei known for his tirades against Israel and its US ally.

US President Donald Trump should tell Israel's leader Benjamin Netanyahu "enough is enough", a former Israeli prime minister told AFP, denouncing the continuation of the war in Gaza as a "crime" and insisting a two-state solution is the only way to end the conflict.