The U.N.'s new envoy to Syria told President Bashar Assad's regime on Saturday that change is both "urgent" and "necessary" and that it must meet the "legitimate" demands of the Syrian people, AP reported. On his first day on the job, Lakhdar Brahimi also called on both sides to end violence in Syria, but said Assad's government bears more responsibility than anyone else to halt the bloodshed. These remarks were seemingly intended to push the Damascus government to ease off on military operations to create a better atmosphere for his peace mission. His comments, made in New York, came as activists said opposition fighters captured an air defense facility in the east of the country near the border with Iraq. The battle for control of Syria's largest city Aleppo, meanwhile, intensified. "I call on parties inside Syria to halt the fighting. Undoubtedly, this call is primarily directed to the government. More than others, it is the duty of governments, under any circumstances and anywhere, not just in Syria, to ensure security and stability for their people," Brahimi told al-Arabiya television in an interview. "The need for change is urgent and necessary. The Syrian people must be satisfied and their legitimate demands are met," he said. The latest violence in Aleppo shows that government forces are still struggling to regain full control of the city from the lightly-armed opposition fighters nearly five weeks after they stormed their way into the city in a surprise offensive. The Syrian Observatory for Human Right activist group said Saturday's clashes in Aleppo were concentrated in several tense neighborhoods - Masaken Hanano, Bustan al-Qasr, Sukkari and Maysar. It reported injuries and damage to buildings, but gave no specific figures.