JERUSALEM — Israel has carried out a series of attacks across the Middle East in recent weeks to prevent Iran from equipping its Arab allies with precision-guided missiles, drones and other sophisticated weapons that could challenge Israel’s defenses.
The attacks represent a new escalation in the shadow war between Iran and Israel, which has broken into the open and threatens to set off a wider confrontation.
In one 18-hour period over the weekend, an Israeli airstrike killed two Iranian-trained militants in Syria, a drone set off a blast near a Hezbollah office in Beirut’s southern suburbs and an airstrike in Qaim, Iraq, killed a commander of an Iran-backed Iraqi militia.
Israel accuses Iran of trying to establish an overland arms-supply line through Iraq and northern Syria to Lebanon. The attacks, only one of which Israel has publicly acknowledged, were aimed at stopping Iran and signaling to its proxies that Israel will not tolerate a fleet of smart missiles on its borders, officials and analysts said.
“Iran is building something here in the region,” said Sima Shine, a former head of research for Israeli intelligence, now a scholar at the Institute for National Security Studies in Tel Aviv. “What’s changed is that the process reached a level in which Israel has to act differently.”
Iranian officials said the Israeli attacks would not go unanswered. Maj. Gen. Qassim Suleimani, commander of Iran’s Quds Force, who oversees covert military operations outside Iran, said on Twitter that “the Zionist actions are insane and will be their last.”
While Iran has not publicly acknowledged the transfer of missile technology, an Iranian with knowledge of Iran’s regional efforts said that in the past year Iran had shifted its focus from training its proxy forces for ground battle in Syria and Iraq to equipping them with high-tech weapons and training.
Leaders on all sides say they do not want an all-out war, but the accelerating pace of violent strikes, often with cheap drones and other covert technologies, has raised the possibility that even a minor attack could spiral into a larger conflict. And public taunting, saber-rattling and domestic politics are all contributing to an atmosphere of volatility and brinkmanship.
The drone blast near Beirut early Sunday destroyed what Israeli officials described as machinery vital to Hezbollah’s precision-missile production effort. Israel’s responsibility for that strike, the aim of which was first reported by The Times of London, was confirmed by two officials briefed on the operation.
In Iraq, bases belonging to Iranian-backed paramilitary groups have been attacked repeatedly in recent weeks, and their leaders have accused Israel, saying Israeli drones had hit their vehicles in Qaim, killing one commander. Israel carried out at least one of the attacks, on a base north of Baghdad on July 19, and American officials have said that Israel carried out others.
On Wednesday, the Lebanese Army said it had fired on two of three Israeli drones that breached Lebanese airspace before returning to Israel.
The flare-ups highlight how Iran’s opportunistic expansion in much of the Middle East is coming up against fierce Israeli pushback.
“The military theater has been broadened by Israel in terms of the targeting of its attacks,” said Randa Slim, an analyst at the Middle East Institute in Washington. “It is no longer about Iranian presence in Syria. It is about Iran’s network in the region.”
For years, as unrest and conflict have weakened Arab states, Iran has moved in, building strong ties with local forces that benefit from its patronage while expanding its influence and amplifying the threat to Israel.
More recently, Iran has strengthened its regional network by providing arms and expertise to the Houthi rebels in Yemen, militias in Iraq and pro-government forces in Syria. Iran has also strengthened cooperation between its allies: Hezbollah operatives from Lebanon have trained fighters in Iraq and Yemen and sent aid to Palestinian jihadist movements, and Iran has airlifted thousands of militiamen from Iraq and elsewhere into Syria to help President Bashar al-Assad defeat a rebellion there.
The lives of the two militants killed by the Israeli strike in Syria over the weekend illustrate the borderless nature of the Iranian network. The fighters, Hassan Zabeeb and Yasser Daher, grew up in Lebanon, studied aviation engineering in Iran and returned to Lebanon to work with Hezbollah, according to the Lebanese news media.
Iran calls its regional network the “axis of resistance.” While its members operate with significant autonomy in their own countries, they share the broader goal of combating American, Israeli and Saudi influence in the Middle East. Having militarized allies across the region also serves as a deterrent against Israeli and American strikes on Iran, since any such attacks could elicit violent responses elsewhere.
Israel’s efforts to hinder Iranian expansion in recent years have focused largely on Syria, where Israel has carried out more than 200 airstrikes since early 2017 on suspected weapons convoys, bases and other sites associated with the Iranian war effort.
Israel mostly avoided killing Hezbollah fighters in Syria and attacking inside Lebanon, which could have provoked counterstrikes. This led to an unwritten understanding — often called the rules of the game — about where and how their conflict would and would not play out.
The attacks last weekend appeared to break the rules by killing two Hezbollah fighters in Syria and reaching into the heart of a Hezbollah stronghold in Beirut.
Raising temperatures further are brash public statements on both sides, which seem intended as much for domestic audiences as for each other.
Israel’s military has taken to taunting its adversaries on social media: After the airstrike in Syria, it ridiculed General Suleimani.
On Tuesday, it launched a Twitter account in Persian to try to undermine him with the Iranian public.
Addressing his followers over the weekend, Hassan Nasrallah, the leader of Hezbollah, vowed to retaliate, shouting his determination to prevent attacks in Lebanon from becoming frequent.
“We in the Islamic resistance, we will not allow for this type of path, no matter the cost!” he said. He did not say how or when his forces would respond.
“I suggest to Nasrallah to calm down,” Prime Minister Benjamin Netanyahu of Israel responded mockingly on Tuesday. “Israel knows how to defend itself and to pay back its enemies. I say the same to Qassim Suleimani: be careful with your words and even more so with your actions.”
Some analysts suggested that the approaching Israeli election encouraged Mr. Netanyahu’s tough stance, while Mr. Nasrallah also could not appear to be weak at a time when American sanctions have hurt his group’s finances.
Talal Atrissi, a sociologist who studies Hezbollah at Lebanese University, said he expected the group to retaliate against Israel to prevent attacks in Lebanon from becoming commonplace.
Alluding to Israel’s national elections on Sept. 17, he added: “There are elections, and Netanyahu needs to show that he is protecting Israel, but if there is no response, he’ll keep doing it. It won’t just be the election. It will become a new strategy.”
Officials and analysts said the recent uptick in strikes, and their spread into Iraq and Lebanon, came in response to adjustments to Iran’s strategy.
One involved General Suleimani’s efforts to maintain supply lines for shipments of arms and equipment from Iran. Until about a year ago, according to a senior Middle Eastern intelligence official, Iran used unmarked or Iranian commercial planes flying into the Damascus airport to reach Hezbollah or Quds Force units in Syria.
But repeated Israeli airstrikes drove Iran to reroute supplies through airfields in northern Syria instead.
When Israel struck those fields, too, General Suleimani moved to set up a land route. That route goes from Iran through Iraq, where drivers and vehicles are often changed to elude surveillance, before crossing into northern Syria.
The Israeli attack on July 19 at Amerli base, north of Baghdad, struck a shipment of guided missiles bound for Syria. It was the first time Israel had carried out an airstrike in Iraq since it destroyed a nuclear reactor near Baghdad in 1981, when Saddam Hussein was in power.
Israel has been working to prevent Hezbollah from manufacturing its own precision-guided missiles since early 2017, using a combination of disclosures, warnings and threats, Israeli analysts say.
Prevented from military action by its understanding with Hezbollah and a desire to avoid war, Israel at first tried to weaponize its intelligence gathering, hoping that exposing Hezbollah’s missile project as a threat to regional security would create international pressure to quash it.
That approach culminated in a speech by Mr. Netanyahu to the United Nations last September, in which he showed aerial photos of what he said were three factories for precision-guided missiles in downtown Beirut.
Ofek Riemer, a former Israeli military intelligence officer who writes frequently on national security, called the public-relations tactic “coercive disclosure.”
But he said that phase appeared to have ended with Sunday’s blast in Beirut.
He cautioned that the explosion in Beirut still appeared well short of an all-out Israeli attempt to stop Hezbollah’s precision-guided missile project by military means.
“We’re still in the signaling business, as I see it,” Mr. Riemer said. “We’re not really going head-on against this project. But it’s also signaling to the international community: Either we take action, and you don’t know where that leads, or you come in and try to pull strings and influence the Lebanese government, Hezbollah by proxy, or even Iran.”