Israeli Defence Forces Chief Yoav Gallant with soldiers after the dastardly attack by Hamas

Israelis awaited word on how Prime Minister Benjamin Netanyahu would respond to Iran's first-ever direct attack as international pressure for restraint grew amid fears of an escalation of conflict in the Middle East.

Netanyahu on Monday summoned his war cabinet for the second time in less than 24 hours to weigh a response to Iran's massive weekend missile and drone attack, a government source said.

While the attack caused no deaths and little damage, thanks the air defences and countermeasures of Israel and its allies, it has increased concerns that violence rooted in the Gaza war is spreading, and fears of open war between the long-time foes.

Israeli military chief of staff Herzi Halevi said on Monday that "this launch of so many missiles, cruise missiles and drones into Israeli territory will be met with a response" but gave no details.

Iranian Deputy Foreign Minister Ali Bagheri Kani told state TV on Monday night that Tehran's response to any Israeli retaliation would come in "a matter of seconds, as Iran will not wait for another 12 days to respond".

But the prospect of Israeli retaliation has alarmed many Iranians already enduring economic pain and tighter social and political controls since protests in 2022-23.

Iran launched the attack in retaliation for an airstrike on its embassy compound in Damascus on April 1 attributed to Israel, and signalled that it did not seek further escalation.

U.S. President Joe Biden told Netanyahu at the weekend that the United States, which helped Israel blunt the Iranian attack, would not participate in an Israeli counter-strike.

Since the war in Gaza began in October, clashes have erupted between Israel and Iran-aligned groups based in Lebanon, Syria, Yemen and Iraq.

Israel said four of its soldiers were wounded hundreds of metres inside Lebanese territory overnight, the first known Israeli ground penetration into Lebanon since the Gaza war erupted, although it has traded fire with the Lebanese Hezbollah militia.

"We're on the edge of the cliff and we have to move away from it," Josep Borrell, the European Union's foreign affairs chief, told Spanish radio station Onda Cero.

French President Emmanuel Macron, German Chancellor Olaf Scholz and British Foreign Secretary David Cameron made similar appeals. Washington and U.N. Secretary-General Antonio Guterres also have called for restraint.

White House national security spokesman John Kirby declined on Monday to say if Biden had urged Netanyahu in talks on Saturday night to exercise restraint in responding to Iran.

"We don't want to see a war with Iran. We don't want to see a regional conflict," Kirby told a briefing, adding that it was for Israel to decide "whether and how they'll respond".

Foreign Minister Israel Katz said he was "leading a diplomatic attack" alongside Israel's military response, writing to 32 countries to place sanctions on Iran's missile programme and proscribe its Revolutionary Guard Corps as a terrorist organisation.

U.S. Treasury Secretary Janet Yellen said Iran's actions threatened stability in the Middle East and could cause economic spillovers. The U.S. would use sanctions, and work with allies, to keep disrupting Iran's "malign and destabilizing activity", she added.

However, some analysts said the Biden administration was unlikely to seek to sharpen sanctions on Iran's oil exports due to worries about boosting oil prices and angering top buyer China.

In a call between the Chinese and Iranian foreign ministers, China said it believed Iran could "handle the situation well and spare the region further turmoil" while safeguarding its sovereignty and dignity, according to Chinese state media.

Russia has refrained from publicly criticising its ally Iran but has also warned against further escalation.

Iran's retaliatory attack, involving more than 300 missiles and drones, caused modest damage in Israel and wounded a 7-year-old girl. Most missiles and drones were shot down by Israel's Iron Dome defence system and with help from the U.S., Britain, France and Jordan.

In Gaza itself, where more than 33,000 Palestinians have been killed in the Israeli offensive according to Gaza health ministry figures, Iran's action drew applause.

Israel began its campaign against Hamas, the Iranian-backed Palestinian militant group that runs Gaza, after Hamas attacked Israel on Oct. 7, killing 1,200 people and taking 253 hostages, by Israeli tallies.

British Prime Minister Rishi Sunak said the Group of Seven major democracies were working on a package of coordinated measures against Iran.

Italy, which holds the rotating G7 presidency, said it was open to new sanctions and suggested any new measures would target individuals.

Iran's attack prompted at least a dozen airlines to cancel or reroute flights, with Europe's aviation regulator still advising caution in using Israeli and Iranian airspace.

(With Agency Inputs)