Syrian warplanes launched a deadly raid Monday on the outskirts of the rebel-held town of Douma northeast of Damascus, killing seven civilians, among them six children, a monitoring group said. "Seven civilians, among them six children, were killed in an air raid on the Shifuniyeh area near Douma," said the Syrian Observatory for Human Rights. At least 13 insurgents were also killed in fierce battles that raged in other areas of Damascus province, said the watchdog which relies on a broad network of doctors, activists and lawyers to compile its reports. Fighter jets also blasted the rebel-held town of Talbisseh in the central province of Homs, as well as Kafraya southwest of the provincial capital, the Observatory said. In the northern province of Raqa, a three-year-old child and his 17-year-old brother were killed in army shelling on the town of Tabaqa, as rebels made significant advances in the province which borders Turkey, it said. At least 40 people, among them 24 civilians, were killed in violence across Syria on Monday, a day after at lest 178 people died, the Observatory said. More than 60,000 people have been killed in Syria's 22-month war, the UN says.