'Hezbollah units are now spearheading the fight against opposition rebel groups while the faltering Syrian army plays a supporting role. Although the militia is highly secretive about the size of its footprint in Syria, Western officials and analysts believe it has roughly 6,000 to 8,000 fighters on the ground there.
The group also refuses to discuss its losses in Syria, but the numbers are substantial and on the rise. Since Hezbollah began taking part in full-fledged combat in Syria in 2013, officials and outside analysts estimate that roughly 700 to 1,000 fighters have been killed or wounded in battle, a substantial loss for the group.
Losing the border town of Zabadani would be a massive setback for the militia, as the town lies along vital land routes that link up Hezbollah-controlled territory with Syria. In the past, Zabadani served as a logistical hub used to transport Iranian arms to the militia.
Iran, which backs Hezbollah as well as other Shiite foreign fighters in Syria, has doubled down on its gamble on the Syrian regime, expanding shipments of weaponry, ammunition, and other equipment.
Tehran also has deployed advisors from the country’s Revolutionary Guard force closer to the front, and some have reportedly taken charge of some operations from Syrian army officers, analysts said.
“They’re running a high-risk, high-reward type of path right now. If it gets to a point where the [Assad] regime looks like it is on its last legs, then Iran has a big decision to make.” '