The Syrian regime and its allies made a sudden advance over the weekend in areas held by Daesh in northwestern Syria, the Syrian Observatory for Human Rights said on Sunday.
The advance of the regime comes two days after Turkey-backed opposition forces took hold of the city centre of al-Bab, a city north of Aleppo previously held by Daesh. On Sunday, the regime army also took the town of Tadef, just north of Aleppo and south of al-Bab, after Daesh withdrew from it, state television reported.
The military action has extended regime control over 14 villages and brought it within 25 kilometres of Lake Assad, the stretch of the Euphrates above Tabqa dam.
By taking Daesh territory south of al-Bab, the regime is moving closer to regaining control of Aleppo's water supply.
Daesh's holdings in northwestern Syria have been eviscerated over recent months by successive advances by three different, rival forces: YPG militants backed by the United States, Turkey-backed opposition fighters, and the regime forces. Turkey considers YPG a Syrian extension of the PKK, a group that Turkey, the US and EU labelled a terrorist organisation.
Turkey's entry into Syria's civil war via their military intervention, named Operation Euphrates Shield in support of rebel groups fighting under the banner of the Free Syrian Army, was intended both to push Daesh from the border and to prevent YPG territorial gains there.
Daesh's loss of al-Bab after weeks of bitter urban warfare marks the group's effective departure from northwestern Syria, once one of its most fearsome strongholds, and an area of importance because of its location along the Turkish border.
Bombings and air strikes in Syria rattle Geneva peace talks
Suicide bombers stormed two regime military installations in Homs on Saturday, killing dozens with gunfire and explosives. The regime's military intelligence chief was killed in the attack.
The brutal bombings threatened to derail the talks held in Geneva. Bashar al-Jaafari, the lead Syrian regime negotiator, demanded the opposition's delegation officially condemn the attacks in Homs.
The opposition's delegation condemned the attack but accused the regime of trying to use the events to derail the negotiations.
"We condemn all terrorist acts done by all terrorist groups. If the Homs operation was done by any of those, it is clear what I say," lead negotiator Nasr al-Hariri told reporters.
"They just want to remain in power. The regime is trying to block the negotiations," he added, saying he would not walk away from the talks.
Regime warplanes carried out retaliatory air strikes against the last rebel-held enclave in the western city of Homs, after holding the opposition responsible.
Tahrir al-Sham, an umbrella group that includes Jabhat Fateh al-Sham (former Al Qaeda affiliates), said in a social media post that five suicide bombers had carried out the attack. It stopped short of explicitly claiming responsibility.
Tahrir al-Sham opposes the talks.