An Israeli soldier takes up position in front of a battery of an Iron Dome air defence system near Jerusalem on Monday. AFP

Israel and Iran traded threats after Tehran's first-ever direct attack on its arch-foe sharply heightened tensions in a region already on edge after six months of war in Gaza.

The war in the besieged territory and its soaring civilian toll have revived the push for a two-state solution, with the UN Security Council preparing to vote Thursday on full United Nations membership for a Palestinian state, according to diplomatic sources.

The United States, meanwhile, announced on Tuesday that it was preparing new sanctions on Iran's missile and drone programme after its weekend attack on Israel, and the EU's foreign policy chief signalled the bloc would levy new punitive measures as well.

Israeli military spokesman Rear Admiral Daniel Hagari said Iran would not get off "scot-free" after Tehran and its allies launched a barrage of more than 300 missiles, drones and rockets at Israel.

"We cannot stand still from this kind of aggression," Hagari said, a day after Israel's military chief vowed there would be "a response" to Iran's attack.

Iran and its allies launched a barrage of more than 300 missiles on April 14.

Iran has characterised the barrage as an act of self-defence following a deadly air strike on its consulate in Syria, saying that it would consider the matter "concluded" unless Israel retaliated.

Iran's President Ebrahim Raisi warned that "the slightest action against Iran's interests will definitely be met with a severe, extensive and painful response".

US President Joe Biden has stressed that "the United States is committed to Israel's security" but wants to prevent the conflict from spreading.

Washington, Israel's top ally and arms supplier, has made clear it will not join Israel in any retaliatory attack on their common adversary Iran, according to a senior US official.

US National Security Advisor Jake Sullivan said Tuesday that Washington would "impose new sanctions targeting Iran, including its missile and drone programme", as well as the Revolutionary Guards and the Iranian defence ministry, in the coming days.

The measures, he said in a statement, would help to "contain and degrade Iran's military capacity and effectiveness and confront the full range of its problematic behaviours".

US National Security Advisor Jake Sullivan speaks during a meeting. File photo

EU foreign policy chief Josep Borrell said Brussels was also working on expanding sanctions against Iran, particularly against its supplies of weaponry -- including drones -- to Russia and proxy groups around the Middle East.

World leaders have urged restraint and de-escalation in the aftermath of the weekend's attack.

During a phone call with Iran's Raisi, Russian President Vladimir Putin called on both sides to "prevent a new round of confrontation fraught with catastrophic consequences for the entire region", the Kremlin said.

UK Prime Minister Rishi Sunak warned his Israeli counterpart Benjamin Netanyahu against "significant escalation" and said now was a moment for "calm heads to prevail".

Agence France-Presse