In the majority-Kurdish Sheikh Makqsud district of the northern Syrian city of Aleppo, Arab rebels and Kurd fighters say they are fighting together against the regime of President Bashar al-Assad. But on the ground, the reality is rather more complex. Standing at the entrance to Sheikh Makqsud, rebel commander Abu Ahmad wears an orange, green and red scarf -- the colours of the Kurdish flag. Nearby, two flags fly together: that of the Kurds, alongside the green, black and white standard of the Syrian revolt. "I wear the colours of my Kurdish brothers, even if I am an Arab," says Abu Ahmad, proudly. He says Kurdish militia loyal to the Democratic Union Party (PYD) -- Syria's branch of the Kurdistan Workers' Party (PKK) -- have "given us ammunition, and their fighters are on the front lines of the battle against the regime". Kurds comprise 10 percent of Syria's total population, with most living in the north of the embattled country. Since the outbreak of the anti-Assad revolt more than two years ago, most Kurds have tried to ensure that their areas remained violence-free. Last summer, Assad's forces withdrew from majority Kurdish areas, and the YPG Kurdish militia became responsible for security there. Although many Kurds feel hostile to a regime that has oppressed them for decades, they have also tried to keep the rebels out of the areas they control in order to avoid sparking a confrontation with the army. When Islamists launched a bid to take over the city of Ras al-Ain in the north, firefights pitted Arab rebels against the Kurds. But in Sheikh Maqsud, where rebels say "Aleppo's biggest battle" is being waged, it appears that past grudges between rebels and Kurds have been set aside, and that the Kurdish militia has joined forces with the insurgents. Thanks to the Kurds' help, "we have blocked the army's supply and reinforcements route near Al-Kindi hospital and the central prison" in northern Aleppo, says Abu Abdullah, who commands a mainstream rebel Free Syrian Army battalion in Syria's second city. "The regime can only use its planes now to bring supplies to its troops," he told AFP. But the army has bombarded the district since insurgents took up positions there. On Saturday, an air raid killed 15 people, among them nine children. In revenge, Kurdish fighters attacked an army checkpoint, killing five soldiers. "There's no difference between us. Together, we fight the same enemy: the regime," says Abu Juan, a Kurdish militiaman. "It's a matter of conscience. We are fighting oppression by the regime," says another Kurdish fighter. But under the surface, feelings of mutual suspicion run deep. Dozens of men wearing the Kurdish YPG militia uniform -- distinct for its yellow star symbol on a red background -- stand at a checkpoint. They are visibly more disciplined and organised than the Free Syrian Army in Aleppo, most of whose checkpoints are manned by young, shabbily dressed fighters. A YPG commander says the Kurds' priority is self-defence. "We are here to protect our people and residents of Sheikh Maqsud, where the PYD has been present for years," he says. "Some FSA rebels are respectable, but others are here just to steal. They break into company premises and loot stuff," adds the Kurdish commander. Because of this, the fighters are well spread out in Sheikh Maqsud. Arab rebels keep a lookout in residential areas of the district, while the YPG is responsible for the industrial part. The FSA, meanwhile, fears that Kurdish residents will provide the loyalist army with sensitive information. "We used to allow a lot of civilians to enter the neighbourhood. But the bombing intensified, and now we are more careful," says Abu Abdullah. Because of the violence, Sheikh Maqsud is becoming a ghost town. At the district's northern edges, civilians are leaving en masse, packing belongings including mattresses, carpets and electrical appliances onto pick-up trucks. "We're fleeing the bombing," calls out one man, as the pick-up he is in drives off.