A car bomb has killed at least 41 people in a rebel-held village near the Syrian town of al-Bab, sources in the region and monitors say.
The explosion destroyed a rebel security post in Sousian, the Syrian Observatory for Human Rights said.
The village is 8km (5 miles) north-west of al-Bab, from which Turkish-backed rebels pushed so-called Islamic State fighters on Thursday.
Turkey says the rebels have "near complete control" of the city.
The attack killed 35 civilians and six rebel fighters, Reuters reported, citing sources in the region. It said the target was a rebel checkpoint.
Civilians were gathering to seek permission to return to al-Bab when the bomb exploded, the opposition-run Qasioun news agency said.
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Situated just north-east of Aleppo, al-Bab has about 100,000 inhabitants in the centre and about 50,000 more living in the suburbs.
It fell to Syrian rebels in spring 2012 and was in IS hands by early 2014, when it became home to many foreign jihadists and their families.
The rebels say they are now working to clear the heavily mined town.
Turkish President Recep Tayyip Erdogan said last year that the capture of al-Bab, the jihadist group's last major stronghold in Aleppo province, would be the prelude to taking Raqqa, seen by IS as its capital in Syria.