On Sunday, a soldier from the Lebanese Army murdered St.-Sgt.-Maj. Shlomi Cohen, 31, of Afula. Two of about ten bullets fired from the Lebanese side of the border hit Cohen in the chest and neck and he lost control of the civilian vehicle he was driving on the Israeli side of the border near a naval base next to Rosh Hanikra.In August, near the same spot, a bomb blew up an army jeep, injuring four soldiers. And in 2010, Lebanese snipers shot at Israeli soldiers on the border, killing one and injuring another. Relatively speaking, however, since the second Lebanon war in 2006, the border has remained fairly quiet.The tragic killing of Cohen, father of a baby girl, does not appear to be a sign of an escalation of tensions.Hezbollah, bogged down as it is in Syria fighting alongside Bashar Assad’s troops against rebel forces, clearly has no interest in opening a front with Israel. And Israel has no interest in escalation either. The IDF has restricted itself to a limited military retaliation, launched a few hours after the unprovoked attack, that reportedly resulted in the injury of two Lebanese soldiers. Further retaliatory operations are unlikely, since attacks staged long after the initial shooting would be interpreted as Israeli aggression.In parallel, the United Nations Interim Forces in Lebanon (UNIFIL) will now attempt to calm down tensions and prevent a potentially volatile situation from deteriorating.High-ranking IDF officers met with their Lebanese counterparts under UN mediation.Under a mandate from UN Security Council Resolution 1701, passed in 2006, the UN forces are supposed to prevent the deployment of Hezbollah forces in Southern Lebanon while strengthening the Lebanese Armed Forces. Although UNIFIL has succeeded in preventing it from maintaining an overt presence in the area, Hezbollah has covert troops operating in the area and has stockpiled over a hundred thousand rockets.But as Brig.-Gen. (res.) Shlomo Brom, a researcher at the Institute for National Security Studies and author of Israel and South Lebanon: In the Absence of a Peace Treaty with Syria pointed out, Sunday’s shooting underlines another worrying development: A large number of young Shi’ite men, many of whom identify with Hezbollah’s ideology, are inducted into the Lebanese Armed Forces under Lebanon’s policy of mandatory military service. And Shi’ites, who make up the single largest religious group in Lebanon, are also the fasting growing, and may become a majority there someday. The Lebanese army soldier responsible for Cohen’s death, who apparently acted alone, was reportedly a Shi’ite. Still, the demographic balance in Lebanon has been upset by the huge influx of mostly Sunni Syrian refugees.According to official estimates, around 800,000 refugees have made their way to Lebanon, over 90 percent of whom are Sunni. Lebanese officials say the number is closer to 1.2 million, since many refugees fleeing the conflict in Syria end up staying with family or in informal arrangements in Lebanon. There is little prospect that any of these newcomers, who make up roughly a quarter of Lebanon’s 4.4 million population, will be returning soon.Similarly to the Palestinians who arrived in Lebanon in 1948 and 1967, these Syrians could easily reignite the sort of civil war that tore Lebanon apart between 1975 and 1990. This time the conflict would be between Hezbollah and other forces inside Lebanon that support Assad and the Sunnis, including the newly-arrived refugees who are rabidly opposed to the Assad regime. The assassination at the beginning of December in Beirut of Hassan al-Laqqis, a commander of Hezbollah troops fighting in Syria’s civil war, apparently by a previously unknown Sunni terrorist organization, should be seen as part of this sectarian conflict.One thing Sunnis and Shi’ites have in common is a hatred of Israel.Quiet on the South Lebanese borders is fragile. Israel must remain vigilant, preparing for the worst case scenario while avoiding unnecessary escalation.Cohen’s tragic killing is a reminder that our region is in upheaval and the relative lull that has characterized our border with Lebanon since 2006 must not be taken for granted.