At least 43 people have been killed after a bomb blast in a rebel-held town in northwest Syria, according to reports.
The explosion ripped through a market in Azaz, close to the Turkish border, and caused significant damage to a government building and a courthouse operated by rebel groups.
According to the Syrian Observatory for Human Rights, the blast was caused by a rigged fuel tanker and severely injured dozens of people.
It said six rebels were among the 48 who died.
Turkish news agency Dogan reported that the bomb was planted by Islamic State. There was no immediate claim of responsibility from the militant group.
Footage from the scene showed a huge plume of black smoke rising from the market, while sounds of gunfire could be heard in the background.
The blast is the worst since a nationwide ceasefire between rebels and the Syrian government came into force last week.
A number of rebels and civilians who were pushed out of Aleppo by the Syrian army resettled in Azaz.
To the west, Syrian Kurdish forces have often tried to advance toward the town, causing friction with Turkish troops and allied Syrian opposition fighters.
Meanwhile to the east, opposition fighters backed by Turkey have been pushing back IS extremists.