Fighting between pro-Turkish armed factions in northern Syria subsided on Sunday after a deal was brokered by Ankara, residents said.
Eight people were killed in the conflict that has been raging in the last few days in the Al Bab region of Aleppo, they said.
The bloodshed indicates the fragility of an alliance of Turkish proxies that Ankara has used against US-backed Kurdish militias, its main adversary in Syria.
The conflict between the pro-Turkish factions has resulted Hayat Tahrir Al Sham (HTS) using fighters in Aleppo governorate, nearer to the border with Turkey, in support of one of the warring groups.
The powerful HTS, which is aligned with Turkey, is based in the neighbouring Idlib governorate. The group emerged after a merger of several radical groups including the Al Qaeda-linked Al Nusra Front, which has changed its name several times since it was founded a decade ago.
But sources in the opposition to President Bashar Al Assad in Istanbul and Amman said HTS fighters have started pulling back under the Turkish-supervised truce agreed on Sunday.
“HTS needs Turkey and understands that it can only go so far in confronting it,” an opposition source in Istanbul said.
Northern and eastern Syria is the main battleground for an international effort by Russia, Iran, the US and Turkey to guard or extend spheres of influence they had carved out since the Syrian revolt began in 2011.
The four countries support, or are aligned with an amalgamation of militias, from Marxist-Leninist Kurdish groups to Sunni extremists and Shiite militants backed by Iran.
The fighting since last week mainly pitted Ahrar Al Sham, which is supported by HTS, against two other groups in the self-declared Syrian National Army, a coalition of rebel groups supervised by Turkey.
The militia organisation was formed from the remains of the rebel Free Syrian Army but has since built its ranks and rearmed with Turkish funding and training.
It is mainly active in areas near the town of Al Bab, situated to the north-east of the city of Aleppo which is under government control, and a strip of territory on the border with Turkey, encroaching on Hasakah governorate where there is a large Kurdish population.
Al Bab forms a frontline between the pro-Turkish groups and Kurdish militias, known as the People's Protection Units (YPG), in the town of Tel Rifaat. The YPG captured Tel Rifaat with Russian air support from anti-Assad rebels six years ago.
Many rebels in the Syrian National Army had moved to northern Syria, mainly from the centre and south of the country, in surrender deals made with the government, supervised by Russia, after it intervened in Syria in support of Assad in late 2015.
A main cause of the fighting among Turkish proxies has been competition over an illicit trade comprising narcotics, oil and human trafficking between YPG-held regions and areas in Turkey's sphere of influence, opposition sources said.
Two residents of the north said an armoured HTS column moved on Saturday from HTS strong holds in Idlib to the outskirts of Afrin in Aleppo governorate, in support of one of the fighting groups, an Islamist militia called Ahrar Al Sham.
“As soon as HTS moved in every other brigade made way,” said one of the residents, who lives in Jindaris, a town near Afrin.
He said HTS fighters who took positions next to Ahrar Al Sham fortifications started returning to Idlib on Sunday.
Turkey deployed the Syrian National Army at least twice in the last four years to capture territory held by Kurdish militias in northern Syria, after tacit approval from Russia.
President Recep Tayyip Erdogan said this month that Turkey would launch a new military operation in Syria to extend what he describes as safe zones along the border.
Mr Erdogan, who did not give a date for the proposed incursion, does not appear to have Russian and US support this time.