Iran has launched an unprecedented drone and missile attack on Israel after warning of retaliation for a strike on its consular building in Syria.

Iran launched over 200 drones and missiles at Israel as its proxies and allies also carried out coordinated attacks on Israeli positions, media reports said.

"The regime in Iran sent a massive swarm of over 200 killer drones, ballistic missiles and cruise missiles," an Israeli army spokesperson told the media.

Iran insisted it acted in "self-defence" after the targeting of its diplomatic mission in Damascus.

The country said it hoped its action would prompt no further escalation and "the matter can be deemed concluded."

US President Joe Biden condemned the attack and promised "ironclad" support for Israel, after holding an urgent meeting with his top security officials over the spiraling crisis in the Middle East.

"I just met with my national security team for an update on Iran's attacks against Israel. Our commitment to Israel's security against threats from Iran and its proxies is ironclad," Biden said on X - earlier known as Twitter.

US forces have been shooting down drones launched by Iran towards Israel, a defence official said. "Our forces remain postured to provide additional defensive support and to protect US forces operating in the region," he said.

President Biden also spoke to Israeli Prime Minister Benjamin Netanyahu over the phone.

Netanyahu, meanwhile, has vowed to respond defensively and offensively, saying that Israel has been preparing for a direct attack by Iran for years.