Israel may carry out a revenge attack on Iran within days, targeting oil sites, nuclear facilities, and key political figures, according to security experts.
It comes in the wake of Iran's attack on Tuesday, in which Tehran reportedly fired nearly 200 missiles at Israel.
Israeli Prime Minister Benjamin Netanyahu struck a defiant tone following the barrage, saying Iran "made a big mistake" and would "pay for it."
"Whoever attacks us — we will attack," he added.
Wall Street's main indexes opened lower on Wednesday amid fears that tensions in the Middle East could escalate into a full-blown war.
Meanwhile, oil prices spiked for a second day on speculation the conflict could limit production. The international crude benchmark was up 2.7% to $75.63 a barrel, and US crude prices rose about 3% to $72.06 a barrel.
Experts speaking to Business Insider said that Israel's counter-strike could be a complete contrast to its measured reaction to Iran's missile and drone attack in April, which caused minor damage to the country's infrastructure.
Yaniv Voller, a senior lecturer in Middle East politics at the UK's University of Kent, said the "Israeli barrier of fear" had been broken — partly because Hezbollah's capabilities have been damaged — and it would likely strike back hard.
Israel has inflicted a series of humiliating blows on Hezbollah in Lebanon, reportedly planting explosives in its pagers, killing its top leaders, and raining missiles on its bases.
It has also spent months conducting airstrikes and raids into Lebanon to degrade Hezbollah's capabilities, and launched a ground and air offensive in the country on Tuesday.
It remains unclear to what extent Hezbollah's capabilities have been damaged.
However, according to Chris Doyle, director of the Council for Arab British Understanding NGO, the Israeli leadership likely believes that an attack on Iran would be "relatively pain-free."
Netanyahu's cabinet believes it has the upper hand, according to security experts.
There remains, however, a huge danger that the war may escalate in ways no one has predicted.
Israel's "defense systems have proven resilient so far amid Hezbollah and Iranian attacks, and the Israeli public is now mostly behind its leadership's offensive maneuvers," said Voller.
However, he added that while Israel has indeed degraded Hezbollah's capabilities, the militant group still retains a huge amount of firepower.
The group likely has stockpiles of up to 200,000 missiles, a report from March by the Center for Strategic and International Studies said.
Clionadh Raleigh, executive director of the Armed Conflict Location and Event Data Project, also cautioned against underestimating Hezbollah's military capabilities.
It is "the largest non-state armed group in the world and has been around for a while," she said, "so while the recent leadership and communications attacks are extremely destabilizing, that does not discount continued conflict from the hex factions stationed across the country."
Doyle said the timing of an Israeli strike would depend on how large a strike it would opt for and whether the US can persuade it not to carry out a "very wide-scale" strike to try to avoid a full-blown regional war.
Doyle and Voller predicted that Israel would strike in the coming days or weeks. Doyle added that it may be even sooner.
"It is likely that the Israeli leadership has already anticipated the Iranian attack and has prepared for it," Voller said.
A senior Israeli official told Axios that Israel's security cabinet meeting did not decide how to respond to Iran's missile attack on Tuesday night.
The source cited Israeli officials, who said they wanted to coordinate their plans with the US.
Another Iranian attack would need more munitions for the Israeli air force, defensive cooperation with US Central Command, and possibly other forms of operational support from the US, Israeli officials told Axios.
Should Israel choose to launch strikes, Doyle expects it to do more damage than those launched in April, and to potentially target Iran's nuclear sites and senior Islamic Revolutionary Guard Corps members.
"All of these are possible, but the United States here also has to play a very key role because the US has a lot of assets in the region," he said, adding: "It could get sucked in as well."
Voller said Iran's capacity to retaliate is "limited," especially after the strategic damage Israel inflicted on Hezbollah, a close Iranian ally, adding that Iran does not have the ability to launch ground invasion or even air raids on Israel.
That means "we may see continuous and intensifying missile attacks on Israeli security and civilian targets as a war of attrition," or even Iranian attempts to hit Israeli and Jewish targets abroad.
Ameneh Mehvar, a Middle East regional specialist with Armed Conflict Location and Event Data, or ACLED, had a different take.
"I still don't believe we are 100% destined for an open-front, full-scale war between Iran and Israel," she said, adding: "Iran is well aware of Israel's military and intelligence superiority and may decide to absorb Israel's attacks."
"However," she said, "I don't see any positive long-term outcomes for the region or the world if this escalation pushes Iran to cross the nuclear threshold in the future due to feeling even more vulnerable given recent development."
Raleigh, who's also of ACLED, said Iran might be banking on a strategy of "death by 1,000 cuts," by inflicting costs on Israel through a three-front war that, in the long run, could be "devastating" for Israel.
"Ultimately," Doyle said, "it's really a failure of international diplomacy to not have de-escalated all of this much earlier with much more urgency, and that's why we got ourselves into this very, very dangerous situation."