Both sides are reporting casualties from Barada which houses the water supply installation for the capital Damascus.
The Syrian regime has now shifted the focus of its fighting to the opposition-held valley of Barada, west of the capital Damascus.
The regime recaptured the whole of Aleppo last week after civilians and rebels were forced out from the besieged eastern districts of the city under a deal brokered by Turkey and regime allies Russia and Iran. Casualties from both sides are being reported from Barada, a valley that houses the water supply for Damascus.
The renewed fight in Barada indicates that a truce between the regime and rebels that was in place in the valley for the water supply has been breached.
The Damascus water authority earlier said rebels were contaminating the capital's water by dumping diesel into the supply line. The authority further said it had temporarily cut off the water supply from Barada to Damascus.
It is not yet clear however, if the aim of the regime-led bombardment, is to take control of the valley of Barada or to bring the rebels to the table to reach a new understanding regarding the water supply.
Meanwhile, the Turkish Army destroyed 140 Daesh targets in Syria's Al Bab district and neutralised 226 Daesh terrorists as part of Operation Euphrates Shield, military officials said on Sunday.
TRT World's Francis Collings brings the latest from Gaziantep.
Separately, Russian President Vladimir Putin and Turkish President Tayyip Erdogan discussed the Syrian crisis in a phone conversation on Sunday, the Kremlin said in a statement.
Diplomatic efforts were underway to establish ceasefire across Syria, President Erdogan's spokesperson said.
The civil war in Syria began in 2011 after Bashar al Assad's regime cracked down on pro-democracy protestors. The ongoing conflict has so far killed at least 400,000 people and displaced millions, according to the UN.