AMMAN/BEIRUT: Syrian militants linked to a former Al-Qaeda affiliate consolidated their grip over large parts of the northwestern province of Idlib Sunday after their main rival evacuated a major border crossing with Turkey, rebels and residents said.

Witnesses said the departing militants, of the Ahrar al-Sham group, had moved a large convoy of heavy equipment and tanks and hundreds of its fighters away from the Bab al-Hawa crossing with Turkey and had headed to areas it controls further south in Idlib province and in the neighboring province of Hama.

Their pullout was stipulated under terms of a cease-fire deal reached Friday following three days of heavy fighting that had pitted Ahrar al-Sham, a powerful rebel group with a foothold across Syria, against Hay’at Tahrir al-Sham, an alliance led by Al-Qaeda’s former Syria branch, Jabhat Fatah al-Sham, formerly known as Nusra Front.

Tahrir al-Sham militants surrounded Ahrar al-Sham near the Syria-Turkey border crossing after rapid advances in a strategic stretch of territory along the border with Turkey and after pushing out their rivals from main towns and villages in the province.

The fighting between the two largest rebel groups that left scores of dead and injured was by far the heaviest interrebel fighting since the start of the conflict.

Tensions have been building between Idlib province’s two biggest insurgent factions mainly over ideological differences between Islamist militant and more nationalist-leaning armed factions.

They have also vied for dominance in the only Syrian province that is entirely under rebel control.

The pullout of Ahrar from the border crossing of Bab al-Hawa, which it had controlled for over three years and that was a major source of revenue, is a big blow for the group.

The cease-fire deal stipulated it would be run by a civil administration in a power-sharing agreement.

In eastern Syria, meanwhile, government forces and their allies have recaptured territory from Daesh (ISIS) in the countryside southeast of its stronghold Raqqa after airstrikes in the area, a pro-Damascus military media unit and the Observatory reported.

The advances toward the provincial boundary between Raqqa and Deir al-Zor took place late Saturday, the War Media Center, run by Damascus ally Lebanese Hezbollah.

The army seized an oil field in the Sabkha area as part of the advance.

It was a rare advance for Damascus’ forces in that area, which is close to territory controlled by the U.S.-backed Syrian Democratic Forces, a Kurdish-dominated alliance separately fighting Daesh.It also brings government forces closer to Deir al-Zor province, another Daesh stronghold. The Syrian army has active front lines with Daesh in western Raqqa and has made gains there.

Also Sunday, Syrian forces carried out air raids on rebel stronghold on the outskirts of Damascus, the Observatory said, a day after it declared a cease-fire in parts of the besieged enclave.

“Regime warplanes targeted the area of Ain Tarma with at least six strikes since early morning, and two raids were carried out on and around the city of Douma,” the Observatory said, without reporting casualties. Regime shelling also hit the outskirts of Jisreen Sunday, the Observatory added.

President Bashar Assad’s forces have surrounded the Eastern Ghouta region for more than four years, and regime forces have regularly targeted the area. They have for weeks been fighting rebels on the outskirts of Ain Tarma, which links Eastern Ghouta to opposition-held parts of the Damascus district of Jobar.

Observatory head Rami Abdel-Rahman said no militant forces were present in the areas targeted by regime bombardment.

The army announced a halt in fighting in areas of Eastern Ghouta Saturday from midday local time, but did not say which areas exactly would be included.

No rebel group yielding influence in Eastern Ghouta said they had signed that agreement.