ISIS militants have executed nearly 700 prisoners in two months in eastern Syria, according to war monitoring group the Syrian Observatory for Human Rights. The prisoners were reportedly among 1,350 civilians and fighters that the so-called Islamic State terror group was holding in territory near the Iraqi border. The slaughter appears to have intensified as the jihadis lost control of more and more land near the town of Hajin, which U.S.-backed forces entered this month. The Syrian Democratic Forces (SDF) have battled ISIS there for months with the help of U.S. special forces. SDF Commander in Chief Mazloum Kobani said he believes 5,000 ISIS fighters remain there, including many who appear ready to fight to the death. The self-proclaimed caliphate has disintegrated across Iraq and Syria, though its fighters still operate in the desert border region and mount guerrilla attacks.