Syrian rebels
Rebel fighters carry their weapons as they run on the front line during a clash against forces of Syria's President Bashar Assad in the Handarat area north of Aleppo Nov. 11, 2014. Reuters/Hosam Katan

Syrian rebels took over several key towns Tuesday near Dara'a in southwestern Syria, liberating several areas that had been held by the regime. Unable to prevail in the northern part of the country where the Islamic State and the regime have carved out strongholds, the rebels are focusing their efforts in the South, an area that has until this month seen little fighting.

The fighting in Dara'a started at the beginning of the month when rebels attacked regime bases in the area. One battle on Nov. 6 led to the fall of Brigade 82, one of the Syrian regime's largest military bases, Al Monitor reported. The rebel group known as the Southern Front told the McClatchy news service that the U.S. airstrikes in Syria had helped them secure areas in Dara'a that opened up a pathway to Damascus.

Last week the rebels seized the city of Sheikh Miskin in northern Dara'a, which sits just 50 miles south of Damascus and is considered the front line for the regime -- the only line that is protecting the capital. Now, the rebels are focused on taking the town of Delli, which would cut the regime's major supply route from Damascus to Dara'a.

Syrian state media reported Tuesday that the army had killed more than 20 rebel fighters in the Dara'a countryside, in the town of Sheikj Miskin. State media claimed the fighters were affiliated with al Qaeda.

Meanwhile, in Aleppo, the regime is trying to hold the towns it controls. For the past several months the military has deployed extra troops to the city to stave off attacks by the Islamic State, also known as ISIS or ISIL. Regime forces have mostly relied on airpower to control their strongholds.

The Syrian Observatory for Human Rights, a monitoring group in the country, said that 13 people, including two children and several women, were killed Tuesday as a result of a regime airstrike against rebel-held areas in the province of Aleppo.

With the regime focusing on the northern part of the country, it is struggling to keep up with the rebel advance in Dara'a. If the rebels continue their progress in the area, taking over neighborhoods and villages along the way, it will eventually meet some of the strongest Syrian military brigades and the only ones protecting Damascus.