Revolutionary Forces of Syria (RFS)

Syria's White Helmets apologize for Mannequin Challenge video

The short video -- a take on the Mannequin Challenge -- was created by the Revolutionary Forces of Syria (RFS), an opposition media group, to draw attention to the crisis amid a renewed aerial assault on the besieged city.

More than 300 people have been killed in Aleppo's rebel-held eastern districts since the Syrian regime resumed heavy bombardment last Tuesday following a three-week lull.

'Error of judgment'