BEIRUT: The straight horizontal white contrails left by Israeli jets criss-crossing Lebanese skies on a near daily basis are a common sight. Less common was the contrail that rose through a blue sky Sunday afternoon in a twisting, weaving path on a near vertical trajectory from somewhere in the Bekaa Valley before dissipating a minute or two later. The contrail, spotted by a Daily Star correspondent in Laqlouq, carried the hallmarks of an anti-aircraft missile launch.

From the direction of the contrail in relation to Laqlouq, the missile launch site appeared to originate from a belt of territory stretching across the Bekaa from Baalbek at the southern end to Younine, 10 kilometers further north.

An-Nahar newspaper reported Monday that two missiles had been fired from the Bekaa “in mysterious circumstances” without further elaborating. The Lebanese Army said in a statement Monday that three Israeli aircraft – two jets and a reconnaissance drone – had flown above Lebanon Sunday. The drone crossed the southern border above Rmeish at 3:10 p.m. and “executed circular flights of the Riyaq and Baalbek regions” before departing Lebanese airspace at 5:35 p.m. above Naqoura, the statement said. The timing and location of the drone flight fits in with the apparent missile launch, which occurred around 4:15 p.m.

This latest sighting comes just four days after the tail of an anti-aircraft missile crashed into an area near the southeast border town of Deir al-Ashayer. The circumstances of that launch are still unclear, although several reports from Lebanese and Syrian media said the Syrian army had shot down an Israeli drone. The Israelis have made no comment on either last week’s incident above Deir al-Ashayer or Sunday’s missile firing in the northern Bekaa.

The two incidents of anti-aircraft fire – a highly unusual development in the context of the Hezbollah-Syria-Israel theater – comes amid increased Israeli aerial activity in Lebanese skies in the past two months and an unprecedented Israeli airstrike against a suspected arms convoy near Damascus three weeks ago.

Numerous reports quoted U.S. and Israeli sources as claiming that the target of the Jan. 30 attack had been one or more SA-17 Grizzly missile batteries, an advanced Russian air defense system. Syria said the target of the raid had been a research facility at Jamraya and broadcast footage of damage to the site.

However, satellite images of the facility taken after the airstrike and broadcast on Israeli television appeared to confirm that the research facility had not been the primary target and only sustained collateral damage when the nearby column of vehicles was struck. Among the damaged vehicles shown on Syrian TV were three SA-8 Gecko anti-aircraft missile launch vehicles.

In 2009, it was reported that Hezbollah units were being trained on the SA-8 Gecko at Syrian military bases, although none of the units were believed to have been transferred to Lebanon at the time. Syria acquired three SA-17 batteries from Russia following Israel’s airstrike against a suspected nuclear facility under construction near Deir al-Zor in northeast Syria in 2007. Two of the batteries were reportedly deployed along the Syria-Lebanon border by April 2012 and the third was retained for training.

Given the lingering, albeit fading, threat of a NATO-imposed no-fly zone over parts of Syria and the fact that there are only three SA-17 batteries in Syria’s possession, it would seem unlikely that Damascus would be willing to hand to Hezbollah one of its most sophisticated air defense systems, assuming the resistance group has the logistical and technical expertise to handle it in the first place. Perhaps the target instead was the SA-8 Gecko batteries shown damaged on Syrian TV. The provision of SA-8 batteries to Hezbollah also would be considered by Israel as a breach of its “red line,” requiring action.

Syria, Iran and Hezbollah condemned the Israeli attack, but there was no immediate retaliation.

Given the circumstances in Syria and the calm along the Blue Line in south Lebanon that has prevailed since the end of the 2006 war, choosing a means of retaliation is fraught with risk.

If Syria and its allies ignore the Israeli strike, it does nothing to dissuade Israel from repeating such actions, particularly as it can be expected that Hezbollah will continue to try and bring into Lebanon arms of sufficient power to uphold its deterrence posture against Israel.

However, a retaliation risks causing an escalation between Hezbollah and Israel the likes of which has not been seen since before the 2006 war. Neither Hezbollah nor Israel appears willing to embark upon another war at this time in recognition of the predicted devastating scale of another conflict, despite the enormous preparations undergone by both sides in the past six-and-a-half years.

That raises the possibility that Syria and its allies are opting for a potential midway solution of shooting down the occasional Israeli drone in Lebanese airspace. Shooting down an unmanned drone might send the requisite message to Israel while diminishing the risk of an unwanted escalation that would be sure to follow the downing of a piloted jet and the loss or capture of an Israeli aircrew.

Furthermore, every Israeli overflight in Lebanese airspace is a breach of U.N. Security Council Resolution 1701 and Lebanon has a right to defend its skies under international law. But then one must ask how many downed drones Israel would be willing to accept before raising the stakes again. Such are the risks of unwanted escalations.

Indeed, Israel has lost at least one drone over Lebanon since 2006 in still unexplained circumstances. In October 2011, an Israeli drone abruptly lost height and then disappeared from UNIFIL-operated radar over Wadi Hojeir near Ghandourieh in the south. The Lebanese Army and UNIFIL searched the valley and found nothing.

The mystery of the disappearing drone persists until today with observers speculating that Hezbollah took control of the drone electronically, landed it safely and whisked it away before anyone turned up. The incident came a month before Tehran announced it had electronically taken control and safely landed a U.S. RQ-170 Sentinel “stealth” drone flying a reconnaissance mission over eastern Iran. The Israelis never admitted to losing a drone, not even to UNIFIL, and the incident has been classified as another example of the secret intelligence war that rages daily between Israel and Hezbollah, yet rarely seeps into the public domain.

Still, it cannot be ruled out that Sunday’s firing was a rare mistake by Hezbollah. Such an error would not be without precedent. In August 2005, three medium-range artillery rockets were launched apparently by accident from then-Hezbollah-controlled Wadi Salouqi in the south near Majdal Silm.

Two of the rockets landed inside Lebanon and the third struck just inside Israel. The incident unintentionally confirmed for the first time that Hezbollah had acquired such rockets (apparently 220mm Syrian Urugans), suggesting a mishap.

To confirm whether Sunday’s missile launch was merely an accident or whether it and last week’s firing near Deir al-Ashayer are examples of a new strategy at play, one must look in the days and weeks ahead to the skies above Lebanon for more coiling vertical contrails.