Jihadists have killed more than 60 Syrian regime fighters in 48 hours, a monitor said Saturday, in some of the deadliest attacks on pro-Damascus forces in recent weeks. Kurdish-led forces in March announced the defeat of the Islamic State group's "caliphate" in eastern Syria, but the jihadists have retained hideouts there and in other parts of the country as well as the ability to carry out deadly assaults. Since Thursday, IS jihadists have killed 35 pro-Damascus fighters in regime-held parts of central and eastern Syria, the Syrian Observatory for Human Rights said.