In an apparent escalation that increased fears of a full-fledged conflagration, Israel's aircraft launched an air attack in Syria, while suspected Israeli drones hit targets in Lebanon and Iraq - all within 48 hours.
Israel in recent years has made no secret of its efforts to deter the advancement of Iran's military influence in the region.
The long-running Syrian conflict has drawn in a number of international forces, including various Iranian-backed militias fighting on the ground alongside Syrian President Bashar al-Assad's troops. Israel has not intervened directly in the war but its fighter jets have regularly bombed Tehran-allied forces such as Hezbollah, a Lebanese group backing Assad's forces.
Yet the attacks on Iraq and Lebanon were seen as a break in the norm for Israel.
"Any country that allows its territory to be used for attacks against Israel will face the consequences, and I repeat, the country will face the consequences," Israeli Prime Minister Benjamin Netanyahu said on Sunday.
His comments came a day after the Israeli military said in a statement it had hit members of Iran's elite Quds Force and Shia militias near Syria's capital, Damascus, alleging that they planned to attack targets in Israel with "killer drones".
Iran denied its forces had been struck, while Hezbollah said on Sunday the air attacks had targeted a house belonging to the movement and killed two of its fighters.
Israel and Hezbollah fought a destructive 34-day war in 2006 that killed more than 1,200 people, most of them Lebanese civilians. Since then, Israel's operations against Hezbollah have been primarily concentrated in Syria - until Sunday.
According to Hezbollah spokesman Mohammed Afif, a small reconnaissance drone fell on a building housing Hezbollah's media centre in southern Beirut on Sunday morning, before a second "explosive-laden drone" blew up in the air and caused damage to the office.
Lebanese President Michel Aoun characterised the drone attack a "declaration of war" that warranted a military response, while Hassan Nasrallah, the Hezbollah leader, blamed Israel and promised a response.
"I say to the Israeli army on the border from tonight, stand guard. Wait for us one, two, three, four days," Nasrallah said on Sunday.
On Tuesday, Netanyahu told Nasrallah to "calm down".
"He knows well that Israel knows how to defend itself and to pay back its enemies," the Israeli prime minister said.
Israel has neither confirmed nor denied the Beirut attack, similar to its stance over another drone assault on Sunday targeting an arms depot owned by the powerful Hashd al-Shaabi force, or Popular Mobilisation Forces (PMF) in Iraq.
Some analysts argued the latest attacks represented a shift from a covert war into a more open one - a change, they say, that has been facilitated by Israel's main ally, the United States.
"There's no doubt in Tehran that the strikes carried out in Iraq were done with the help of the US," Iranian political analyst Mohammad Marandi said. "The Americans therefore are just as implicated in these strikes as the Israelis are."
The PMF also alleged that the US had assisted Israel in attacking their base in the town of al-Qaim with two drones, which led to the death of one fighter.
"This blatant attack came with air cover over the area from American planes, in addition to a large balloon to monitor the area near the site of the incident," it said in a statement on Sunday.
In recent months, the US has intensified its "maximum pressure" campaign against Iran, spearheaded by President Donald Trump's unilateral decision last year to pull Washington out of a 2015 nuclear deal signed between Iran and world powers, and the reimposition of sanctions to cripple the Iranian economy.
Shortly after Trump's controversial move in May 2018, Israel carried out air raids against what it said were Iranian targets in Syria in response to rocket fire targeting its forces in the occupied Golan Heights, which it blamed on Tehran.
"What is important to recognise ... is the degree of impunity which Israel is acting under is directly related to the degree that the United States itself greenlights its allies to engage militarily," Trita Parsi, the executive vice president of the Quincy Institute for Responsible Statecraft, said.
What this showed, Parsi argued, was that type of blessing from Washington was actually destabilising the Middle East, noting that the attack on Iraq was particularly alarming given that it is a strong ally of the US.
"Israel has engaged illegally in three different Arab countries without the approval of these governments by violating their airspace and essentially acting with a tremendous degree of impunity," he added.
"There have been no protests or objections from Europeans, and nothing has been brought to the United Nations," he continued, arguing that things would be very different had another country engaged in a similar bombing campaign.
A series of mysterious blasts have targeted arms depot belonging to the Iranian-backed PMF over the past month. Last week, unidentified US officials speaking to US media said Israel was behind one such attack, signalling a significant escalation in Israel's years-long campaign against what it sees as Iranian military assets in the region.
Netanyahu, who is facing a tough election rerun next month as well as the possibility of being indicted over a number of corruption allegations, had previously hinted to reporters that Israel was behind the series of attacks against Iranian-backed militias in Iraq over the past month.
"I don't grant Iran immunity anywhere," he said on last Thursday. "Obviously I've given the security forces the order and the operational freedom to do what is necessary in order to disrupt these plots by Iran."
But Marandi said Netanyahu was "sacrificing the interests of his government for the sake of self-preservation", arguing that the prime minister was "reckless" and "desperate" because of the multiple cases against him.
"The Israelis gain nothing from the strikes because all they do is give Hezbollah and its allies a very valid and legitimate reason to strike back," he added.
Yet Ronen Bergman, an Israeli investigative journalist and author of The Secret War with Iran, disagreed.
"I would expect Netanyahu to do whatever he can not to have a confrontation before the elections," he said. "If we look at the previous elections that took place last April, Netanyahu was doing whatever he could not to follow the hardline ultra-right-wing pressure to engage in a military offensive into Gaza."
Bergman said Israel was responding to "operational and intelligence reasons".
"Israel decided it would not allow Iran to have a military build-up in Syria ... Things are happening, Israeli intelligence is learning about them, and Israeli military forces are taking action to destroy them."
Bergman referred to a July speech made by Yossi Cohen, in which the chief of Israel's Mossad intelligence agency reiterated Israel's long-held position that it would not tolerate Iran and allies expanding their footprint in southern Syria.
Iran and Hezbollah "are setting up bases and factories for sophisticated weaponry in Iraq and Lebanon", Cohen said at the time. "They mistakenly believe that we will have difficulty reaching them there."
The attacks in three different countries have raised the stakes but uncertainty remains whether the bellicose rhetoric will dissipate, lead to retaliatory raids or escalate to an all-out war.
Marandi said Iran or its allies would have no choice but to respond, "otherwise the Americans and Israelis, separately and together, will become more aggressive and behave with greater impunity".
In a Twitter post following the weekend attacks in Syria and Lebanon, Major General Qassem Soleimani of Iran's Islamic Revolutionary Guard Corps (IRGC), said: "These insane operations are absolutely the last tries of the Zionist regime."
For his part, Netanyahu said on Monday Iran was plotting attacks against Israel and urged the international community to "act immediately so that Iran halts these attacks".
Yet for all the bellicose rhetoric, Parsi said a direct military confrontation between Israel and Iran that would lead to full-scale war looked unlikely.
"I don't see any evidence of Iran willing to engage in a fight with Israel," Parsi said, arguing that Israel felt Iran was in a risky position to respond amid the fallout from the US's decision to withdraw from the nuclear deal.
Also, if a substantial response was elicited, then Iran could be playing right into Israel's hands, he added.
"If there is some sort of larger response from Iranians, then yes I can definitely see Netanyahu seeing how that would be beneficial to him," Parsi said. "The Israeli public would likely rally around the flag and be quite loath to change leadership in the middle."
Simultaneously, if Israel continued with its course of action in Lebanon, it was likely to risk eliciting a response from Hezbollah, Parsi said.
"But at the same time, it may be exactly what Netanyahu is looking for," he added.