Tensions between Israel and Iran-backed militant groups in Syria and Lebanon soared overnight after weeks of tit-for-tat attacks, increasing risks of a regional war, said analysts. Just hours after Lebanon’s Hezbollah claimed to have downed an Israeli drone on Monday morning, Israel said that Iran-backed militias had launched a “number of rockets” from Syria towards Israel that failed to reach their target. An Israeli army spokesperson warned that the Syrian regime would “pay a heavy price for allowing Iranian and Shiite militias to operate from within its territory”. In parallel, a pro-opposition monitor of the Syrian war reported that “unidentified warplanes” bombed the Al Bukamal region in eastern Syria, killing 18 pro-Iranian fighters. The strikes started on Sunday night and continued on Monday morning. Saudi network Al Arabiya reported that the explosions targeted militant groups affiliated with the Popular Mobilization Unit militias (PMF). The raid comes after a string of mysterious attacks against the PMF. The Shiite paramilitary group has previously blamed Israel, which does not usually comment. Last week, Fox News reported that Iran was establishing a new military base in Syria in Al Bukamal, which is located near the Iraqi border. Israel views Iran as its main enemy. In what Israeli media has dubbed a “quiet war”, Israel has intensified its crackdown on Iran-backed groups across the region with sporadic bombings in Syria and Iraq as the 2015 nuclear deal between Iran and world powers unravels. "It's clear that we are in the midst of an expanded Israeli aerial campaign targeting Iran's regional proxies, one that Iran has yet to develop an effective response to," Firas Maksad, adjunct professor at George Washington University, told <em>The National</em>. “Tensions will continue escalating,” said director of communications at Carnegie Middle East Center, Mohanad Hage Ali, warning that they might increase after Israeli parliamentary elections on September 17. “If [Israeli Prime Minister] Benyamin Netanyahu is re-elected, he will probably try to score against Iran and its proxies once and for all.” Regional tensions have been on the rise since US President Donald Trump unilaterally pulled America from the 2015 accord last year. On Saturday, Iran said it had begun using advanced centrifuges, in violation of the deal that European diplomats have failed to salvage. Israel’s military operations in the region have been met with outrage in Lebanon, pushing Hezbollah to retaliate to save face despite the group initially shying away from confrontation. Most of its manpower is still deployed in Syria, propping up President Bashar Al Assad in the eight-year civil war. Hezbollah is also experiencing financial difficulties since the US re-imposed sanctions on Iran. But the explosion of an Israeli booby-trapped drone in Hezbollah stronghold’s in south Beirut in late August, hours after two of the group’s fighters were killed by an Israeli airstrike near Damascus, pushed Hezbollah to retaliate one week later in a limited cross-border raid that left no casualties near the Israeli military base of Avivim. By targeting Hezbollah in south Beirut, Israel broke an unwritten rule by both parties not to attack each other on their own territory, said Hezbollah leader Hassan Nasrallah. The tacit agreement had been broadly respected since the end of the month-long 2006 Hezbollah-Israel war in which nearly 1,200 Lebanese (mostly civilians) and 158 Israelis (mostly soldiers) were killed. Nasrallah vowed that from now on, there would be “no more red lines” against Israel and that Hezbollah would shoot down Israeli drones that regularly breach Lebanese airspace with little to no response from the Lebanese State or Hezbollah. However, Nasrallah clarified that Hezbollah did not have the capacity to shoot down every single Israeli drone buzzing over Lebanon. Hezbollah followed through on its promise early Monday morning, stating in a press release that it had downed an Israeli drone flying over south Lebanon. A reporter working for Hezbollah-affiliated Al Manar TV tweeted that the drone “was equipped with high-precision listening and spying devices and was on a military mission.” The Israeli army confirmed it had lost a helicopter-style drone but claimed that it had simply crashed and that there was “no concern” that intelligence could be gathered from it. Lebanese officials did not comment. Echoing Nasrallah’s threats, deputy chief of Hezbollah’s executive council, Ali Daamoush, said on Saturday that “after the Avivim operation, a new phase has begun, a phase of open response which does not take into account any red lines against any aggression that the Israeli enemy may carry out against our country.” Hezbollah MP Muhammad Raad struck a defiant tone on Monday, claiming that the group was stronger than ever thanks to a “solid coalition.” Mr Raad was seemingly referring to Hezbollah’s alliance with mostly Christian Free Patriotic Movement party founded by President Michel Aoun and now headed by his son-in-law and foreign minister, Gibran Bassil. “Let them impose sanctions as they please, we will continue our work, we are determined to reach our goals, and we will not allow Israel to take our land, not even our sky,” boasted Mr Raad, the state-run National News Agency reported. The US recently increased its financial sanctions on Hezbollah, its MPs and on a Lebanese bank with alleged ties to the party. However, despite its threats, Hezbollah has avoided causing Israeli casualties up to now, signalling that the group wishes to avoid an all-out war that would be costly for the cash-strapped party and that would cause severe damage to Lebanon, which is already plagued by an economic crisis, weak infrastructure and a high refugee population. Another reason that the Israeli-Hezbollah tit-for-tat has remained contained up to now is because of Russian mediation, Lebanese media reported. Russia enjoys good relations with both Israel and Syria, enabling Israel to go after Iranian interests on Syrian territory as long as it does not target the Al Assad regime, said Mr Maksad. “Israel’s campaign of fire from the sky surely has its limitations and carries risks of escalation, but Netanyahu has set in place the necessary deconfliction arrangements with Russia,” said Mr Maksad. “Netanyahu is betting that response from Iran and Hezbollah will remain limited. So far, that bet appears to be paying off,” he added.