Syrian rebels have kidnapped hundreds of Syrian Kurds in the northern province of Aleppo, the Britain-based Syrian Observatory for Human Rights said Monday. The kidnappers are holding the hostages in a town north of Aleppo, the Observatory said, giving no further details about the circumstances of the kidnapping. An earlier report said some Kurdish militants were battling rebels in northern Syria near the border with Turkey on Monday, one day after deadly clashes between the two sides killed 11 rebels. The clashes reportedly ignited when radical rebels stormed the Kurdish-dominated Ras al-Ein town and demanded to control one of the checkpoints. Also in Aleppo, a mass grave of government troops was discovered Monday near the Koerse military airport in the countryside, the Observatory said, spelling no further details.