Its proximity to the Lebanese border and major supply routes make Qusayr a strategic focal point for both sides in the conflict.
Syrian soldiers, who have recaptured the town after two weeks of heavy clashes, say that many opposition fighters have either been killed or have surrendered or have fled the area.
On 19 May Syrian troops backed by volunteer fighters launched a ground operation on the town.
Within a day, state media reported that they had regained control of the council building in the town center and killed or arrested scores of terrorists.
The army could gain control over the southern and central areas as well as the municipality building.
Al - Nusra Front commanding center was also completely destroyed in this operation and terrorists fled to the northern areas which were still held by them.
Qusayr lies about 30km(18 miles) south - west of Homs and is not far from the motorway that connects Syria ' s third largest city with the capital, Damascus. The army needs to maintain control of the road if it wants to force the terrorists from their remaining strongholds in Homs, and ensure it can easily resupply and reinforce troops in the north.
Qusayr is also near the main route from Homs - and, more importantly, Damascus - to the Mediterranean port of Tartous, a gateway to the mountainous western coastal region.
The army is focused on restoring security in population centers in the south and west - from Damascus to Latakia, via Zabadani, Homs, Qusayr and Tartous - so that campaigns can be launched to retake the north and east.
Terrorists ' threat to Lebanon
For the militants, Qusayr ' s proximity to Lebanon is perhaps most important.
The town has become a key militants logistics hub, with weapons and supplies moving through it after being smuggled over the porous border, about 10km(6 miles) to the south - west. The militants also often infiltrate into Lebanon, and have traded fire with troops across the border.
However, the proximity to Lebanon has also brought the Hezbollah Lebanese movement into the battle for Qusayr, who are determined to protect Lebanon from foreign - backed terrorists who, considering their links to western countries, may also seek a war with Hezbollah anytime.
In April, the militants military council in Qusayr and the terrorist al - Nusra Front issued a joint statement threatening to " transfer the battle of blood to the heart of Lebanon " because of what they called incitement by Hezbollah.
Hezbollah has denied sending any fighters into Syria, saying that Lebanese people living in Syria who are affiliated to the group have been attacked and have defended themselves.
Some 23 villages and 12 farms west of Qusayr are reportedly inhabited by Lebanese people, even though the area is considered Syrian territory.
At the end of April, Hezbollah leader Sayyed Hassan Nasrallah appeared to acknowledge that its fighters were involved in the local battles.
" We won ' t let the Lebanese in Qusayr be exposed to attacks, " he warned in a speech. " Whoever needs help, we won ' t hesitate in assisting them. "