With the Syrian civil war well into its third year, the western town of Qusair near the Lebanese border has become the latest site of urban warfare in the grueling fight between President Bashar Assad's military and the rebels trying to overthrow his regime. Below is a look at issues at play as the battle for the town rages on for a third straight week.


A town of about 40,000 people, Qusair is located in Syria's central province of Homs in a mountainous area about 15 kilometers (9 miles) from the Lebanese border. The majority of residents are members of Syria's Sunni Muslim majority, just like most of the rebels fighting Assad's regime, dominated by minority Alawites, members of an offshoot sect of Shiite Islam. Syrian Christians also live in the city and in surrounding villages along with many Shiites, mostly of Lebanese origin.


The Syrian government is fighting for Qusair because it wants to reassert its control over the town that is strategically located between Damascus, the seat of Assad's government, and the Alawite heartland near the Mediterranean. The Syrian military has been joined by elite forces from Lebanon's Shiite Hezbollah group, militants who are a staunch ally of the Assad regime and have a vested interested in its survival.

Opposition forces want to hold on to the overwhelmingly Sunni town that has served as a conduit for shipments of weapons, fighters and supplies smuggled from Lebanon to the rebels inside Syria. Rebels in Qusair have called on fighters from all over Syria to come to their aid in the town.


Thousands of civilians are trapped in the town, some of them gravely injured, according to activists inside. Appeals by the United Nations and other aid organizations to allow humanitarian aid workers enter Qusair have gone unheeded. A doctor in the town says 300 seriously wounded residents, mostly women, children and the elderly require evacuation for medical treatment. He says doctors have been treating people in unsterilized shelters after the town's main hospital was destroyed in the fighting. They've exhausted oxygen supplies and are running out of antibiotics, bandages and anesthetics.


Rebels fighting to oust Assad had controlled Qusair for more than a year, but came under intense pressure in recent weeks as government troops poured into the area as part of an offensive. Backed by Hezbollah guerrillas, Assad's forces stormed the town from the south and east on May 19 and captured more than half of it within hours. Rebel units including the al-Qaida-affiliated Jabhat al-Nusra group have dug in to its northern and western areas, putting up fierce resistance and killing dozens of Hezbollah fighters. A large number of Syrian and foreign fighters is also suspected to have been killed in the fighting.


The rebels had plenty of time to build underground bunkers and tunnels before the battle. In recent days, rebel reinforcements from northern Syria have arrived. Sniper fire from both sides is widespread.


The battle for Qusair has highlighted both the sectarian overtones of the conflict and the growing role of militant Islamic groups — both Sunni and Shiite — in the Syrian war. Hezbollah's increasing involvement in particular underlines the regional sectarian aspect of the conflict, in which an Iranian-backed Shiite axis faces off against Sunnis supported by Gulf Arabs in a proxy war extending into neighboring Lebanon and Iraq. The fighting in Qusair has also complicated joint U.S.-Russia efforts to convince the government in Damascus and the Cairo-based main opposition group to end the bloodshed through a negotiated settlement. So far, the violence in Syria has claimed more than 70,000 lives.