At least 60 members of the Syrian army and allied militias were killed on Saturday in a major attack by the rebel Southern Front alliance in the southern city of Daraa, field sources told Zaman al-Wasl.
Rebels, including Al-Qaeda's Syria wing, the Nusra Front, announced Thursday a fierce offensive on Syrian regime forces in Daraa, stating their aim was to "purify" the area, according to AFP.
Southern Front mortar and artillery shells pounded the regime’s political and military intelligence headquarters, government complex and Ash Sharq Hotel in Daraa.
Activists say the regime-controlled Daraa hospital is overcrowded with Syrian army fatalities.
In retaliation, Syrian air forces extended its aerial bombardment in the rebel-held countryside of Daraa.
Opposition fighters already control parts of the city and about 70 percent of the province, which borders Jordan.
Operation "Storm of Truth" was announced on Twitter by the Southern Front, "to purify the province of Daraa from the filth of the gangs of [Bashar] Assad".
The offensive appears to be a continuation of an assault launched in June under operation "Southern Storm."
According to activists, a number of senior rebel commanders have been killed in the fighting, including Zakariya al-Abboud, leader of Fallujat Houran Division, Mohammad Abdulrahim al-Ghanem, commander of Ahrar Mzeireeb, Jalal al-Masri, senior commander in Yarmouk Army, and Colonel Hussein al-Heraki.
Syria's southwestern corner is of strategic importance due to its proximity to Damascus and neighboring states Israel and Jordan. It is also the last significant foothold of mainstream rebels, who have largely been crushed elsewhere in Syria by government forces or jihadist groups.