In recent weeks Israel and Hizballah continued a time-honored tradition that tends to flare up in the hot months of summer: exchanging harsh words and threats regarding what each side will do to the other in the next war. These are not empty threats. Each side has the ability to inflict tremendous damage on the other. But even though both sides are ready for a war, neither Israel nor Hizballah wants one now. The main purpose of their heated rhetoric is the maintenance of deterrence and alertness. However, a recent development might raise the temperature even more.

In a speech at the Herzliya Conference on June 22, Israel’s head of military intelligence, Maj. Gen. Herzi Halevi, basically confirmed prior reports in Arab media that the Iranian Revolutionary Guard Corps (IRGC) is working to establish an independent weapons industry in Lebanon focused on advanced missiles. This worrying development reportedly had become the focus of the Israel Defense Forces (IDF) and the Israeli cabinet in recent weeks, with some wondering if there will be a point at which Israel will need to execute a preemptive strike in Lebanon that might spark a war.

Why the Iranian Shift?

In recent years Israel attacked numerous arms shipments on their way to Hizballah. These advanced arms shipments reportedly included anti-ship missiles, surface-to-air missiles, and surface-to-surface ballistic missiles. Some of these missiles are accurate and can hit strategic sites in Israel, such as military bases and important civilian infrastructure. The Israeli prime minister and minister of defense time and time again said such capabilities in the hands of Hizballah would be a red line and insisted that Israel will act to prevent the flow of advanced weapons to the militant group. According to some estimates, Israel was able to destroy 60 percent of these advanced arms shipments. This might be cause for celebration, but it seems that these airstrikes changed something in Iran’s thinking.

Israeli media reported this week that the IRGC is pushing for a Hizballah-controlled advanced weapons industrial base because this would make Israel’s interdiction operations obsolete. Tehran likely hopes that Israel will avoid attacking Hizballah in Lebanon, fearing that such a direct attack might lead to war. As such, the closer the production line is to the customer, the better.

Iran’s calculus has some merit. It appears that Israel and Hizballah have an unspoken understanding: As long as Israel does not attack Hizballah on Lebanese soil and its attacks do not result in Hizballah casualties, the organization usually chooses not to retaliate. As Amos Harel, one of Israel’s leading national security journalists, noted, in recent years Israel targeted weapons shipments in Lebanon only one time, and after that Hizballah tried to retaliate using different proxies in the Golan.

For Iran, beyond avoiding the reach of the Israeli Air Force, there are other likely reasons to shift production to Lebanon. Iran will be able to avoid the logistical difficulties and costs of shipping these missiles from Iran to Syria and then to Lebanon. And if everything works out, Hizballah will likely have a larger and more advanced missile arsenal at its command, thereby strengthening its deterrence vis-à-vis Israel. Moreover, Iran will be able to have another hub for weapons production and distribution, not only to Hizballah, but also to other proxies in the region and beyond.

Will Israel’s Calculation Change?

Last month, Israel warned Iran through European countries about this plan, which might suggest that these “factories” are still not up and running, and it is not yet clear what will be their capacity and to what extent they will improve Hizballah’s military arsenal in quantity and quality. Hizballah already has an estimated arsenal of more than 150,000 rockets and missiles, so if Israel did not go to war until now, why is this development different?

The main difference touches on Hizballah’s ability to produce its own “tie-breaking” weapons, as Prime Minister Netanyahu called these advanced missiles. If Hizballah can build missiles with heavy payloads and advanced guidance systems, this creates a serious problem for Israel. Hizballah will be able to increase its arsenal of missiles that can hit any target in Israel and inflict significant damage. True, Israel has advanced missile defense systems, but if Hizballah will have hundreds of those advanced missiles, some will surely hit their target. So this is the dilemma: If Israel believes that a war with Hizballah is inevitable, as Hizballah is an Iranian proxy, and the Iranian regime keeps saying it wants to destroy Israel, then does not it make sense to act now before Hizballah becomes even stronger?

There is no simple answer. Israel almost always prefers to avoid a wider conflict, meaning long weeks of fighting that can hurt Israel’s economy and put a significant burden on its population. This is of course true on its northern front, as Hizballah’s military capabilities are much more advanced than Israel’s other foes, namely Hamas, and the costs to Israel will be significant. For that reason, any Israeli prime minister will think long and hard before launching an attack in Lebanon, especially because he or she will know the Israeli public will demand an explanation as to why a devastating war was necessary. Be that as it may, some might think that a one-off attack will not result in a war and can be manageable. If you asked some Israeli security analysts 10 years ago what will happen if Israel targets arms shipments on Syrian soil, some would have probably answered “war,” but today this happens with some regularity. Hizballah is and will probably continue to be preoccupied in Syria in the short term, meaning it might prefer to avoid a significant operation against Israel, so perhaps an Israeli military strike in the short term makes sense.

What are key Israeli officials saying? Defense Minister Lieberman said the government is “fully aware” of the missile factories and understands “what needs to be done.” But he also added, “There’s no need for either hysteria or euphoria on this issue.” He continued, “The State of Israel has no interest in initiating a military move, not in the north and not in the south,” suggesting that any preemptive strike in Lebanon is not on the table. Israel’s Chief of Staff, Lt. Gen. Gadi Eisenkot, said on July 5 “that Israel’s priority vis-à-vis Hizballah is to prevent the Shiite group from improving the accuracy of its missiles and rockets,” but he added that Israelis need to “put things in perspective and not panic.”

Iran’s continued efforts to establish these weapons factories in Lebanon will increase the tensions on the Israeli-Lebanese front. For now, as this plan appears to be only in its early stages, and it seems that cool heads still prevail on both sides, there is still time to act diplomatically to avoid an escalatory scenario.

Nadav Pollak is a terrorism analyst at the Center on Extremism (Anti-Defamation League). He is a former Research Fellow at the Washington Institute for Near East Policy. Pollak also served as an NCO in the IDF Intelligence Corps.