BEIRUT — Clashes have been raging along the Lebanese-Syrian border since May 6 between Hezbollah militants and the Syrian army, on the one hand, and the militants of the Islamic State (IS) and Jabhat al-Nusra, on the other. These clashes are highly significant and might have various outcomes and dimensions for what has become known as the Qalamoun battle. To understand the situation, some factors should be put into perspective.

Qalamoun is a mountainous region along Syria's western border with Lebanon. Its rough barren lands stretch along 600 square kilometers (231 square miles) and includes a mountain range that rises over 2,000 meters above sea level. The region stretches from Syria's Zabadani region in the southwest to an-Nabek in the northeast. Given the area's wide range, it includes a pathway to Damascus in the southeast and to Homs in the north.

Hundreds of militants affiliated with the terrorist groups fighting in Syria have sought refuge in this region after losing their positions in several neighboring areas. They lost the Qusair battle in June 2013 and an-Nabek battle in March 2014. Reportedly, thousands of IS and Jabhat al-Nusra terrorists, among other groups, made this rough mountainous area their stronghold.

Qalamoun is adjacent to Lebanon from the central Bekaa Valley, along the eastern border with Syria. Since Qalamoun is adjacent to mountainous and barren Lebanese lands, it is a natural pathway toward three Lebanese regions facing it to the west: Arsal in the north, West Bekaa in the south and Britel-Baalbek in between.