Syrian refugees and citizen journalists are sharing bleak videos of the conditions in Aleppo, as tens of thousands attempt to flee the city amid the breakdown of a ceasefire between government and rebel forces.

Many of the videos show lines of people shuffling out of the city's blasted eastern neighbourhoods, where the rebels made their last stand against the forces of President Bashar Al Assad on Tuesday. The ceasefire declaration was meant to end hostilities and allow the rebels to leave the city with those caught in the crossfire, but that deal appears to have broken down. Fighter jets resumed dropping bombs on rebel-held neighbourhoods early Wednesday, and evacuation buses have been forced to turn back into the city.

Video from the streets of Aleppo shows Syrian refugees marching in long lines away from the destruction, carrying few personal belongings. One video, which was posted by a pro-government news organization, says the refugees were received by Syrian and Russian troops.

Activists say the first convoy heading out of southern Aleppo was actually forced to turn around, due to a reported dispute among pro-government forces over timing.

American documentarian Bilal Abdul Kareem posted a video early Wednesday, in which he encouraged social media users to pressure their governments to intervene in Aleppo.

"Stay engaged. Stay educated," he says in the video. "It appears when people disengage, the sounds of war are stoked again."

Kareem also vents his frustration over the collapse of the ceasefire. Explosions can be heard in the background during the video.

Kareem also shed some light on the internet situation in Aleppo, where many have been able to get out their messages despite the heavy bombing. "The internet continues to come and to go," Kareem says. "Mostly it's off."

The account for Bana Alabed, the seven-year-old Aleppo resident with more than 284,000 Twitter followers, issued a frustrated tweet on Wednesday. "Dear world, there's intense bombing right now. Why are you silent?" said the tweet, which was signed by Bana's mother, Fatemah. "Fear is killing me and my kids."

Fatemah Alabed also called for Turkey to intervene.

Several videos posted online show citizen journalists walking through the deserted, bombed-out city, often with the sound of explosions in the background.

With files from The Canadian Press