The Syrian regime army scored its second important victory in two days with backing from Russian air power on Thursday, as the groundwork was being laid for crucial international talks this weekend in Vienna.
State television announced the capture of Al-Hader, a former opposition bastion near the key Aleppo-Damascus highway, just 48 hours after regime forces broke a siege by the Islamic State (ISIS) group of the Kweyris air base in the east of Aleppo province.
Bolstered by the launch of Russian air strikes in Syria in late September, President Bashar al-Assad's forces have launched a series of offensives to regain ground lost in the country's internecine civil war.
A new push to resolve the conflict has meanwhile gathered pace, with diplomatic officials already arriving in Vienna ahead of talks bringing together some 20 countries and international bodies on Saturday.
And in parallel, ISIS claimed responsibility for twin suicide bombings that killed more than 40 people in a stronghold of the Iran Shi'ite terror proxy Hezbollah in the southern suburbs of Beirut, Lebanon.
It was the deadliest attack yet on a Hezbollah bastion since the terrorist organization entered the conflict in Syria in early 2013 in support of Assad's regime.
A military source told AFP that regime troops and allied forces were in "full control" of Al-Hader, a town around 25 kilometers (15 miles) south of Syria's second city Aleppo.
The source said fighters from Hezbollah as well as Iranian forces had participated in the operation.
"Most important advance"
The Syrian Observatory for Human Rights monitor confirmed regime forces had taken control of large parts of Al-Hader, though it said fighting was ongoing inside the town.
It said both Syrian and Russian warplanes were carrying out strikes in the area.
"The town is the biggest headquarters for rebel forces in southern Aleppo, and capturing it would bring the army closer to the key Aleppo-Damascus highway," Observatory chief Rami Abdel Rahman said.
Al-Hader was largely controlled by Al-Qaeda affiliate Nusra Front and other allied Islamist groups, he said.
After taking Al-Hader, Syrian forces and allied fighters quickly advanced west, entering the town of Al-Eis, the Observatory said.
"Fighting is ongoing inside Al-Eis. The area is key because it is elevated and if they capture it they will have line of fire sight over the Aleppo-Damascus highway," Abdel Rahman said.
"Today's advance is the most important strategic advance for Syrian regime forces since the Russians began their air strikes," he said.
The capture of Al-Hader comes after regime forces on Tuesday entered the Kweyris military base in Aleppo province, breaking an ISIS siege that had lasted for more than a year.
The Observatory said Thursday that more than 100 combatants had been killed in the battle for the base, where around 1,000 regime troops had been trapped for months.
A military source told AFP Thursday that the army planned to use the airport as a forward operating base for new offensives against ISIS in the province.
"Kweyris airport is not just an air base but an integrated military base and taking control of it will give joint Syrian and Russian forces an advance post from which to launch other operations," the source told AFP.
Moscow blasts US
Two of three working groups had meanwhile begun gathering in Vienna ahead of Saturday's talks, a diplomatic source said.
The two groups will focus on what are expected to be the key topic of the meeting – drawing up an opposition delegation to negotiate with Assad and determining which rebel groups will be designated as "terrorists" at the best of Iran, which ironically is the leading state sponsor of terror.
Both issues are likely to be contentious, with deep divisions between Arab and Western countries, on the one hand, and Russia and Iran, Assad's key allies.
A third working group, focusing on humanitarian questions, is to begin gathering on Friday, the source said.
Neither representatives of the Syrian regime nor opposition groups are expected to attend Saturday's talks, the second after a round of discussions in Vienna on October 30.
Moscow has put forward a peace proposal for the talks, which calls for elections after an 18-month constitutional reform process, but Western officials have dismissed the plan as it does not ensure that Assad will be removed from power.
Moscow hit back on Thursday, with foreign ministry spokeswoman Maria Zakharova blasting Washington.
"The United States hastily organized meetings of Syria working groups…without consulting Russia," she said. "This can clearly be seen as an attempt to divide participants.
She noted that countries such as Iran, Iraq and Lebanon were not part of the working groups, adding, "we cannot accept these rules of the game."
AFP contributed to this report.