Damascus: Over 6,000 people have fled areas in northern Syria as a result of the attacks by the Islamic State (IS) militants, a monitor group reported on Sunday. The mass exodus was witnessed in the towns of Sheikh Issa, Mare' and other towns in the northern province of Aleppo as a result of the IS attacks on these areas that are under the control of the US-backed Syrian Democratic Forces (SDF), Xinhua news agency reported. The Islamic State has recently unleashed a wide-scale offensive on the SDF controlled areas in the northern countryside of Aleppo, in retaliation to the SDF attacks on the terror group's positions in the northern countryside of the province of al-Raqqa, the de facto capital of the IS. The SDF managed to repel the IS attacks on Mare', which is considered as the "capital of revolution" by the Syrian rebels, as the town was the first to witness armed insurgency that spread to the city of Aleppo in the early years of Syria's five-year-old conflict. The Syrian Observatory for Human Rights said the people fled to other areas under the SDF control, adding that tough humanitarian situation is prevailing in such towns as a result of the military showdown there. The SDF, which has recently been formed from Kurdish and Arab fighters, unleashed an offensive to control areas in northern al-Raqqa under heavy US air cover. The observatory, which relies on a network of activists on ground, said the SDF advance has slowed down, as the IS militants were prepared well for the battle. The aim of the SDF offensive was to control a triangle between Aleppo and al-Raqqa to cut the IS routes between both provinces. Mare' is also of great significance as it borders Turkey and constitutes an important supply line to the rebel fighters in northern Aleppo.