Sharjah 24 – AFP: Israel was on alert Thursday after its arch-foe Iran threatened reprisals over a strike in Syria this month that killed two Iranian generals, and as the war against “Hamas” ground on in Gaza.

Days after Israel strengthened its air defences and paused leave for combat units, the United States also warned of the risk of an attack by Iran or its allied groups at a time Middle East tensions have soared.

Iran is "threatening to launch a significant attack on Israel," US President Joe Biden said Wednesday, pledging "ironclad" support for its top regional ally despite diplomatic tensions over Israel's military conduct in Gaza.

Israel was widely blamed for an April 1 attack that destroyed Iran's consulate building in Damascus and killed seven members of the Islamic Revolutionary Guard Corps (IRGC), including two generals.

Iran's supreme leader, Ayatollah Ali Khamenei, on Wednesday warned that Israel "must be punished and will be punished", days after one of his advisors had said that Israeli embassies are "no longer safe".

Israeli Foreign Minister Israel Katz swiftly replied to Khamenei on social media site X that "if Iran attacks from its territory, Israel will respond and attack Iran".

Biden said he had told Israeli Prime Minister Netanyahu that "our commitment to Israel's security against these threats from Iran and its proxies is ironclad".

"Let me say it again -- ironclad. We're going to do all we can to protect Israel's security."