Iran and allies won't back down from Israel: Khamenei

Iran and its regional allies will not back down from Israel, Supreme Leader Ayatollah Ali Khamenei says, after an Israeli attack on Beirut that is thought to have targeted the heir apparent to Tehran-backed Hezbollah's slain leader.

Iran raised the stakes when it fired missiles at Israel on Tuesday after its arch-foe assassinated Hezbollah secretary general Hassan Nasrallah, a towering figure who turned the group into Lebanon's most powerful military and political force with reach across the Middle East. Israel has vowed to respond.

"The resistance in the region will not back down even with the killing of its leaders," Khamenei said in a rare appearance leading Friday prayers in Tehran, mentioning Nasrallah in his speech and calling its attack on Israel legal and legitimate.

He did not mention Hezbollah official Hashem Safieddine, rumoured to be Nasrallah's successor.

Axios reporter Barak Ravid cited three Israeli officials as saying Safieddine had been targeted in an underground bunker in Beirut overnight.

Safieddine's fate was not clear, Ravid said on X.

Israel's military declined comment and Hezbollah made no comment on Safieddine's fate.

His brother Sayyed Abdallah Safieddine, who is Hezbollah's representative to Iran, attended Khamenei's speech in Tehran.

Iran's proxies in its "Axis of Resistance" - Hezbollah, Yemen's Houthis and armed groups in Iraq - have carried out attacks in the region in support of the Palestinians in the Gaza war.

Khamenei said Afghanistan should join the "defence".

Israel has assassinated leaders and commanders of Hezbollah and Hamas, the Palestinian militant group it has been seeking to wipe out in Gaza since its attack on Israel a year ago.

Israel's military said on Friday it had eliminated the head of Hezbollah's communication networks, Mohammad Rashid Sakafi, by conducting a "precise, intelligence-based strike" in Beirut on Thursday.

US President Joe Biden suggested Israel's response to Iran's missile salvo, which it fended off with its extensive defences, could include a strike on Iran's oil facilities.

Beirut's southern suburb of Dahiyeh, a stronghold of the Iran-backed Hezbollah, came under renewed strikes near midnight on Thursday after Israel ordered people to leave their homes in some areas, residents and security sources said.

Huge explosions shook the sky in the vicinity of Beirut's main airport in the early hours of Friday, and Lebanese civilians said they were living in constant fear.

Israeli strikes also sealed off Lebanon's main border crossing with Syria.

Lebanese Transport Minister Ali Hamieh said Friday's strike on the Syrian border hit inside Lebanese territory near the crossing, creating a four-metre-wide crater.

The Israeli Defence Forces had accused Hezbollah of using the crossing with Syria to transport military equipment into Lebanon.

Tensions between Iran and Israel have been high as Israel has been weighing options to respond to Tehran's ballistic missile attack on Tuesday, which Iran had carried out in response to Israel's military action in Lebanon.

US President Joe Biden said he did not believe there is going to be an "all-out war" in the Middle East, as Israel weighs options for retaliation, but that more needed to be done to prevent one.

While the United States, the European Union, and other allies have called for an immediate 21-day ceasefire in the Israel-Lebanon conflict, Biden said the US was discussing with Israel its options for responding to Tehran's assault, which included Israel striking Iran's oil facilities.

His comments contributed to a surge in global oil prices, and rising Middle East tension has made traders worry about potential supply disruptions.

However, Biden added: "There is nothing going to happen today."

Asked later if he was urging Israel not to attack Iran's oil installations, Biden said he would not negotiate in public.

Nations have prepared contingency plans to evacuate citizens from Lebanon. Although no country has launched a large-scale military evacuation yet, some are chartering aircraft. People are also fleeing on their own.

Israel says its operations in Lebanon seek to allow tens of thousands of its citizens to return home after Hezbollah bombardments during the Gaza war forced them to evacuate from its north.