Iranian officials should determine how best to demonstrate Iran's power to Israel after the Israeli attack on Iran two nights ago, Iran's official IRNA news agency cited the country's Supreme Leader Ayatollah Ali Khamenei as saying on Sunday.

"The evil committed by the Zionist regime (Israel) two nights ago should neither be downplayed nor exaggerated", IRNA cited Khamenei as saying, Reuters reported.

Iran on Saturday played down Israel's overnight air attack against Iranian military targets, saying it caused only limited damage, as U.S. President Joe Biden called for a halt to escalation that has raised fears of an all-out conflagration in the Middle East.

Scores of Israeli jets completed three waves of strikes before dawn against missile factories and other sites near Tehran and in western Iran, Israel's military said.

Khamenei said Iran's power should be demonstrated to Israel, adding that the way to do so should be "determined by the officials and that which is in the best interest of the people and the country should take place".

Israel said it struck military sites in Iran early on Saturday in retaliation for Tehran's attacks on Israel earlier this month, the latest attack in the escalating conflict between the heavily armed rivals.

Iranian media reported multiple explosions over several hours in the capital and at nearby military bases, but there were no immediate reports of damage or casualties, according to Reuters.

Before dawn, Israel's public broadcaster said three waves of strikes had been completed and that the operation was over.

The Middle East has been on edge awaiting Israel's retaliation for a ballistic-missile barrage carried out by Iran on Oct. 1, in which around 200 missiles were fired at Israel and one person was killed in the West Bank.

Tensions between arch rivals Israel and Iran have escalated since Hamas, the Iran-backed Palestinian militant group based in Gaza, attacked Israel on Oct. 7, 2023. Hamas has been supported by Lebanon-based Hezbollah militants, also backed by Iran.

Fears that Iran and the U.S. would be drawn into a regional war have risen with Israel's intensifying assault on Hezbollah since last month, including airstrikes on the Lebanese capital Beirut and a ground operation, as well as its year-old conflict in the Gaza Strip.

"In response to months of continuous attacks from the regime in Iran against the State of Israel – right now the Israel Defense Forces is conducting precise strikes on military targets in Iran," Israel's military said in a statement.

The military said later that it had completed its "targeted" attacks against military targets in Iran, adding that its planes had safely returned home.

Israel has the right and duty to respond to attacks from Tehran and its proxies, which have included missile strikes launched from Iranian soil, the military said.

Targets did not include energy infrastructure or nuclear facilities, a U.S. official said.

U.S. President Joe Biden had warned that Washington, Israel's main backer and supplier of arms, would not support a strike on Tehran's nuclear sites and has said Israel should consider alternatives to attacking Iran's oil fields.

Iranian authorities have repeatedly warned Israel against any attack.

"Iran reserves the right to respond to any aggression, and there is no doubt that Israel will face a proportional reaction for any action it takes," the semi-official Tasnim news agency said on Saturday, quoting sources.

IRAN PLAYS DOWN STRIKES

Iranian state TV quoted a military spokesman as saying the explosions heard in Tehran were linked "to air defense systems reacting to efforts by the Zionist regime (Israel) to attack three locations outside the city of Tehran."

Videos carried by Iranian media showed air defences continuously firing at apparently incoming projectiles in central Tehran, without saying which sites were coming under attack.

The semi-official Iranian Fars news agency said several military bases in the west and southwest of Tehran had also been targeted.

Tasnim said Islamic Revolutionary Guard Corps bases that were attacked were not damaged.

A spokesperson for Iran's Civil Aviation Organization said flights on all routes were cancelled until further notice, state news agency IRNA reported.

Neighbouring Iraq also suspended flights in all of its airports until further notice, its state news agency said.

Israel targeted some military sites in Syria's central and southern parts with airstrikes early on Saturday, Syrian state news agency SANA reported. Israel has not confirmed striking Syria.

U.S. INFORMED AHEAD OF STRIKES

Israel said Prime Minister Benjamin Netanyahu, Defense Minister Yoav Gallant and other security officials were closely following the operation at the military's command and control centre in Tel Aviv.

Gallant spoke to U.S. Defense Secretary Lloyd Austin shortly after Israel's response began, a U.S. defence official said.

The United States was notified by Israel ahead of its strikes on targets in Iran but was not involved in the operation, another U.S. official told Reuters.

U.S. Secretary of State Antony Blinken, in the Middle East for another attempt to broker a peace deal, said on Wednesday Israel's retaliation should not lead to greater escalation.

Even as it sought to convince Israel to calibrate its strikes, the United States moved to reassure its closest ally in the Middle East that it would aid in its defence should Tehran decide to stage a counter-attack.

This included Biden's decision to move the U.S. military's THAAD anti-missile defences to Israel, along with about 100 U.S. soldiers to operate them.

An Israeli strike killed at least three journalists and wounded several others as they slept in guesthouses in southern Lebanon on Friday, Lebanon's health ministry said, in what Beirut declared a war crime.

U.S. Secretary of State Antony Blinken said there was an urgency to get a diplomatic resolution to the conflict in Lebanon, a day after he said Washington did not want to see a protracted campaign there by its ally Israel, Reuters reported.

Israel launched its major offensive in Lebanon a month ago, saying it was targeting the heavily armed, Iran-backed Hezbollah to secure the return home of tens of thousands of Israelis evacuated from the north due to cross-border rocket attacks.

Beirut authorities say the offensive has killed more than 2,500 people and displaced more than 1.2 million people, the majority of them over the last month, creating a humanitarian crisis.

"We have a sense of real urgency in getting to a diplomatic resolution and the full implementation of UN Security Council Resolution 1701, such that there can be real security along border between Israel and Lebanon," Blinken said in London.

He said it was important so "people at both sides of the border can have the confidence to... return to their homes".

The journalists killed were camera operator Ghassan Najjar and engineer Mohamed Reda of the pro-Iranian news outlet Al-Mayadeen and camera operator Wissam Qassem, who worked for Hezbollah's Al-Manar, the outlets said in separate statements.

They had been staying in the southern town of Hasbaya when it was hit around 3 a.m. (midnight GMT). The town, inhabited by both Muslims and Christians, had not previously been targeted.

It was the deadliest attack on media in Lebanon since hostilities erupted between Israel and Hezbollah just over a year ago, prompted by the Gaza war.

There was no immediate comment from Israel, which in general denies deliberately attacking journalists.