The rooftops ahead belong to the regime. Abu Mohammed checks his Dragunov rifle and chambers a round. He removes a piece of stone from a small hole bored into the wall.
He squints through the scope and waits as warplanes scream above.
"The main challenge is seeing where the Government snipers are," he says.
Minutes earlier he and his spotter flitted across back streets in Aleppo's Sheikh Saeed district, which has seen some of the heaviest fighting in the city, and into an abandoned apartment moving silently up a stairwell covered in debris. Holes large enough for a person to crawl through were smashed into the walls, creating a maze of sniper routes throughout the building.
They ducked low and ran across a veranda littered with shell casings, up another flight of stairs and crawled out on to the roof.
Mohammed says he learned to snipe 20 years ago while serving in the military; the same military he is now fighting as the 20-month insurgency against Syrian President Bashar al-Assad grinds on.
While the Free Syrian Army (FSA) insurgents have recently made some gains in the country - overrunning military bases, leading to speculation that the tide is turning in their favour - the contest for Aleppo has been reduced to a bloody stalemate.
With little opportunity for direct confrontation between the two sides, the conflict has stagnated, along with international diplomatic efforts, becoming a sniping war in which territory is gained or lost corner by corner.
Snipers hunker down on rooftops throughout the city. Mortar rounds whistle overhead, while helicopters menace from above: the Syrian president has increasingly deployed warplanes and helicopters, waging a war from the skies.
"We will not stop," says Mohammed. "Not until all of Aleppo is liberated."
Yet it is hard to see how cosmopolitan Aleppans could feel "liberated". Since the FSA swept into the city in July, both parties to the conflict have committed war crimes. And the insurgents are mostly the rural poor, not from the metropolitan centres of Damascus and Aleppo.
"In the countryside, life is much simpler," says Abu Fathy, from the at-Tawhid Brigades, the militia to which Mohammed belongs. "I face many complications in the cities: the people think differently, have different customs."
The war has turned Aleppo, an ancient city and home to more than two million, into an urban dystopia. Towering apartment buildings have had their fronts shorn off by missiles. The makeshift Dar al-Shifa hospital is ruined, bombed a week ago by Assad's warplanes. The attack reportedly killed 15 people.
Rubbish chokes the gutters and pavements, huge piles stretching the length of some streets. Children pick through the festering remains as dogs bay and scrap. Bombed car shells sit overturned in pools of stagnant water sent spewing from burst pipes.
Mohammed Kafrawi, 40, has been selling his family's jewels to buy food. "The war has gone on too long, we are tired of this," he says.
Trucks block streets, providing cover from errant sniper fire; people stand in endless queues, waiting to buy bread.
The FSA fighters are conservative Sunni Muslims who have acquired an increasingly intolerant Islamicist shade, which threatens to obscure smaller demographics.
Syria, with a population of 23 million, is home to Sunni, Druze, Alawite and Christians.
On the FSA-occupied streets of Aleppo, missionaries from Hizb ut-Tahrir (The Party of God) openly hand out pamphlets, seeking the creation of a global Islamic caliphate.
Fighters from the hardline and al-Qaeda-linked Jabhat al-Busra brigades travel in reckless caravans through streets atop pick-up trucks mounted with anti-aircraft guns. Black bandannas are wrapped around their heads.
At a rally in Aleppo's Tariq al-Bab district on Friday, members of the brigade worked themselves into a frenzy, chanting: "Assad is the enemy of God".
One local vendor, Mohammed Sabbagh, describes the Syrians' plight.
"It is getting worse every day. There are no jobs. More people are going hungry, coming to me and begging for food," he said. "But I am making 150 Syrian pounds a day. What can I do?"By Glen Johnson