Islamist militants have reportedly beheaded dozens of soldiers at a Syrian army base and mounted their heads on poles. Extremists from the group Islamic State, previously known as ISIS, seized the base in the northern province of Raqqa, leaving more than 85 soldiers dead and 200 more unaccounted for. The Syrian Human Rights Observatory said at least 50 of the soldiers had been executed - many of them beheaded - as horrifying footage began circulating online which appeared to show the bodies.