Israel’s war cabinet has met to discuss its response to Iran’s unprecedented drone and missile attack.
Israel did not make public whether a decision had been reached.
Its allies have strongly condemned Iran’s actions, but urged Benjamin Netanyahu’s government to show restraint.
While Iran has signalled it considers the matter closed, the Israeli military’s chief of staff said the attack would not go unanswered.
“Look, as we look forward, we weigh our steps, and this launch of so many missiles, cruise missiles, UAVs to the territory of the State of Israel will be met with a response,” Lt Gen Herzi Halevi said.
He did not specify a course of action, or give a timescale.
Former CIA head David Petraeus had told BBC Radio 4’s World Tonight programme that Washington does not want to risk the wellbeing of the global economy with any Israeli retaliation against Iran.
Gen Petraeus, who also commanded the international forces in Iraq and Afghanistan, said the Iranian attack was a “very big deal”, and that the West had to understand how significant this was for Israel.
“The challenge now, of course, is that there are somewhat different perspectives on what to do next. If for some reason the Brent crude prices spike, or if there is some kind of freedom of navigation issue in the Gulf. And there is already some concern over Iran taking an oil tanker the other day.”
Gen Petraeus, who is now retired now, said the debate inside the Israeli government was about how to formulate a response that would show Israeli deterrence without “ratcheting up the escalation any further”.
He added that Israel had a number of asymmetric options that could allow it to respond without increasing tension.
Lt Gen Halevi was speaking from Nevatim air base in southern Israel, which sustained damage in Saturday’s overnight attack but was said by Israel to be “still functioning”.
Tehran said the operation was retaliation for a 1 April strike on its consulate in Syria, which killed senior Iranian military commanders.
The Israeli military said more than 300 drones and missiles were launched at Israel. It said almost all were brought down by its forces, with support from the US, UK, France and other countries, before reaching their targets. No deaths were reported and Israel said the damage was limited.
World leaders have urged restraint amid concerns about a major escalation in tensions in the Middle East.
US President Joe Biden spoke to Mr Netanyahu following the launch of the Iranian attack and reaffirmed “America’s ironclad commitment to the security of Israel”.
But on Sunday the US told Israel it would not join in any counter-strike on Iran, according to a senior White House official.
“We’re committed to a ceasefire that will bring the hostages home and prevent the conflict spreading more than it already has,” Mr Biden said on Monday.