A well-attended Christmas tree-lighting ceremony in the Syrian city of Aleppo was rocked by an explosion meters away from the gathered crowd. No casualties have been reported.

“We saw a huge flash of light,” reported RT’s Lizzie Phelan, who was covering the event, in an online broadcast. “At least half of the people on the square immediately fled.”

Phelan said that eyewitnesses were unsure if the explosion was produced by a launched mortar or a planted explosive device.

Moments earlier, Azizieh square, in western Aleppo, which is under firm government control, began hosting its first Christmas tree-lighting since fighting broke out in the city in 2012.

Balconies of houses around the square were festooned with Syrian and Russian flags, as hundreds of members of the Christian minority of what was once Syria’s biggest city, celebrated a symbolic return to normality, following the recapture of the city by government forces earlier in December.

A brass band played seasonal standards, and many filmed the ceremony – an unusual sign of ordinary civilian life – on their smartphones.

Across the city, the UN-monitored evacuation of rebels and civilians who do not wish to live under government control is close to completion. Government forces are expected to enter the eastern districts of Aleppo within days.