BEIRUT, Aug 16: Syrian warplanes struck targets in a rebel-held district in the contested northern city of Aleppo on Friday, killing at least 15 people, wounding dozens of others and leaving some buried under the rubble of buildings, activists said.

The Britain-based Syrian Observatory for Human Rights and the Aleppo Media centre said the airstrike targeted three buildings that were almost completely flattened in the rebel-held district of Kalassa, killing at least four children. They said many people were missing and residents were struggling to save people trapped under cement blocks and debris.

The Observatory said the death toll was likely to rise because many of the wounded were in critical condition and others were missing.

The Aleppo Media Center, which tracks violence in the city, said 33 people were killed and over a hundred wounded in the airstrike. The different figures could not be reconciled. Aleppo has been the focus of a violent struggle for control since rebel forces pushed in and began fighting with government troops there last summer. Activists also reported heavy fighting in several areas of the country, including the contested Qaboun district on the edge of the capital Damascus. Government troops have been trying to dislodge rebels from the area, which they use to lob mortars into the city.

Also on Friday, the UN refugee agency said an unusually large wave of Syrian families has been pouring into Iraq's Kurdistan region this week. Adrian Edwards, a spokesman for the Office of the UN High Commissioner for Refugees, said thousands of Syrians — mainly from Syria's largest city, Aleppo, and several poor northeastern Syrian regions — were part of a “sudden, massive movement” into northern Iraq.

He told reporters in Geneva that up to 7,750 Syrian refugees a day had crossed a Tigris River bridge over the border, but said the reasons for the surge were unclear. Fighting, however, has intensified in the eastern Deir el-Zour province bordering Iraq in recent days, as rebels attempt to extend their advances there. Syrian army warplanes conducted several air raids against rebel positions in recent days.

Edwards says UNHCR staff saw “scores of buses” dropping people off on the Syrian side. Iraq is already home to more than 150,000 refugees from Syria, where Kurds are the largest ethnic minority.—AP