The number of people killed in several days of clashes between Syrian security forces and loyalists of former President Bashar al-Assad, followed by large-scale massacres, has risen to more than 1,000, a human rights monitoring group said on Saturday, marking some of the deadliest violence since Syria's civil war began 14 years ago. Since Thursday, escalating hostilities in the governorates of Tartus, Lattakia, Homs and Hama have also resulted in civilian injuries, displacement and damage to civilian infrastructure.