Syrian regime on Friday stepped up its aerial and artillery bombardment on the eastern countryside of Daraa province, killing two people, local activists said.
The heavy shelling targeted Allajat region at the border with Jordan and the towns of al Karak and Rakhm.
Activists said the regime warplanes had conducted at least 12 raids and its helicopters had dropped more than 18 barrel bombs.
Rebels in return have targeted Khelkhela military airport in Sweida province with rockets and mortar rounds.
Russia, Iran and Turkey struggled Wednesday to hammer out details on a plan for safe zones in Syria at a fifth round of peace talks in the Kazakh capital Astana as the regime negotiator cast doubt on any major developments from the discussions.
Moscow and Tehran, which back Bashar al-Assad, and rebel supporter Ankara agreed in May to establish four "de-escalation" zones in a potential breakthrough towards calming a war that has claimed an estimated 470,000 lives since March 2011.
The regime army had suspend combat operations in southern Syria for two days this week including in Quneitra province, where Israel has hit army outposts in recent days