Israeli Prime Minister Benjamin Netanyahu and his immediate war cabinet are considering what action to take following Iran's attack on Saturday.
Allies including the United States have urged Israel not to risk igniting a wider regional conflict, and President Joe Biden has made clear U.S. forces would not join any retaliatory attack on Iran.
Israel could respond to the Iranian barrage with air strikes of its own, particularly as Iranian air defences are considered much less well developed than the multi-layer system that Israel and its allies deployed on Saturday night.
An Israeli air force officer told a briefing with reporters that the air force was ready to defend Israel and added: "Some of defence is to react and attack if needed."
"And that is put to our government and the cabinet and for them to decide how, when and if," the officer said.
Such an attack could hit strategic facilities including Revolutionary Guards bases or nuclear research facilities.
Former intelligence officials say it would be less likely to hit civilian infrastructure such as power plants, and would need to avoid civilian casualties. This would be both to ensure no further loss of international support and also because of the assessment that the Iranian authorities are vulnerable to popular pressure over political repression and the dire economic situation. Significant civilian casualties would be considered likely to rally Iranian public support behind the government.
Israel could also hit proxy groups such as Hezbollah in Lebanon or Iranian targets in countries such as Syria and Iraq. However, the fact that Iran directly attacked Israel for the first time suggests that any such action would be only part of a wider response that would also target Iran itself.
Israel is believed to have carried out numerous cyber attacks in Iran over the years, on infrastructure ranging from petrol stations to industrial plants and nuclear facilities, and a repeat is considered among the likely options for retaliation.
Any such attacks could interfere in highly visible areas such as energy production or flight services. As with direct air strikes, former intelligence officials say they believe Israel would avoid attacks on infrastructure such as hospitals to reduce the impact on the general population.
Israel is believed to have previously carried out a number of covert operations inside Iran, including the assassination of several of its senior nuclear scientists.
In addition to military and intelligence strikes against Iran, Israel is stepping up diplomatic efforts to isolate Tehran, including by extending sanctions. Foreign Minister Israel Katz has also renewed pressure on European countries to join the United States in declaring Iran's Revolutionary Guards to be declared a terror organization.
(Reporting by James Mackenzie, editing by Timothy Heritage)
