The attack in Beirut early Sunday morning, which has been attributed to Israel, hit a central component of Hezbollah's missile program. It damaged a planetary mixer — an industrial-sized mixer weighing about eight tons, needed to create propellants that can improve the engine performance of missiles and increase their accuracy. The machine was hit, as far as we know, shortly before Hezbollah planned to move it to a secured site.

Hezbollah chief Hassan Nasrallah, who accused Israel of carrying out this strike and a second one – which killed two Lebanese Hezbollah fighters near Damascus a few hours earlier – threatened retaliation for both strikes. The Israeli army is readying for a reprisal, possibly within the next few days.

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A Hezbollah reprisal is likely to include fire targeting Israel Defense Forces units on the Lebanese or the Syrian border, or even firing a missile deep into Israeli territory. The assumption is that Nasrallah will try to keep the response "below the threshold of war," but it's difficult to know whether he can fully control the consequences. In addition, Iran's Revolutionary Guards' Quds Force, led by Gen. Qassem Soleimani, might try to carry out a retaliatory strike of its own.

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The aerial strike in Beirut, which Nasrallah said was conducted by two explosive-laden drones sent by Israel, hit the mixer, which had been temporarily placed in a Hezbollah-controlled area of the city's Shi'ite quarter Dahiyyeh. The mixer was damaged, but the main blow was to the machine's control panel, which is separate from the mixer itself.

Replacing the controller, an expensive bit of electronics manufactured in Iran, will likely take a long time. Were the mixer to become operational, it could have enabled Hezbollah to set up a production line capable of turning out rather large quantities of precision-guided long-range missiles. Because of its use in manufacturing ballistic missiles, the mixer was delivered to Hezbollah by Iran in violation of international treaties.

Open gallery view Hezbollah's retaliations to attacks they attributed to Israel Credit: Haaretz

In the past few years, foreign media outlets — as well as a few high-ranking Israeli officials — have reported hundreds of Israeli Air Force strikes targeting arms convoys sent by Iran to Hezbollah in Lebanon, via Syria. In addition to damaging shipments of precision missiles, they hit precision accuracy kits, which are meant to be retrofit onto missiles already in Hezbollah's arsenal to improve their performance. The weapons smuggled in these shipments were heavy and relatively prominent; Hezbollah likely figured out that Israel can easily identify them and sought an alternative method.

In his address to the UN General Assembly in September, Prime Minister Benjamin Netanyahu revealed that Iran and Hezbollah were building three underground sites for manufacturing and converting precision missiles in the Beirut area. The factories were vacated within a few days. The latest strike in Beirut will probably significantly delay Hezbollah's missile program.

Soleimani's retaliatory failure

The Israeli strike Saturday night in the village of Aqraba, southeast of Damascus, was the product of extended intelligence surveillance of Quds Force activities. Soleimani sought to avenge attacks ascribed to Israel against arms stores belonging to the Revolutionary Guards and pro-Iranian Shi'ite militias in Iraq and Iran. The task was assigned to the Imam Hossein Division, also known as the international division, a Shi'ite force that reports to Soleimani in Syria and is active in the country's civil war and in its efforts against Israel.

The cell that planned drone attacks targeting Israeli sites in the Golan Heights included two Lebanese men, former Hezbollah members who joined the Quds Force. As far as is known, Nasrallah was unaware of the plan. On Thursday evening, the cell approached the Israeli border, on the foothills of Mount Hermon, but the IDF foiled their attempt to fly two drones into Israeli territory.

The cell was identified the following day in a private, guarded home in Aqraba. On Saturday night, the Israel Air Force fired at the building, killing the two Lebanese militants.

In Lebanon, a different drone strike, allegedly by Israel, was reported Monday. It was said to have been carried out early Monday morning in Lebanon's Bekaa, against the Popular Front for the Liberation of Palestine – General Command, the Palestinian militant organization founded by Ahmed Jibril. In retrospect, that report appears suspect; the attack may very well not have happened.