Islamic State (IS, formerly ISIS) militants accompanied by relatives surrendered to the Syrian Democratic Forces (SDF) by the hundreds on Thursday, the SDF said. It added that its fighters had made progress into the remaining IS-held part of the enclave in eastern Syrian near the Iraqi border. IS insurgents have been mounting a last-stand defense of the enclave at Baghouz, the final patch of IS territory that once spanned a third of Iraq and Syria and which has been besieged by the SDF for weeks, Reuters said. The jihadists had sought to counter-attack three times in two days, deploying more than 20 suicide bombers, according to the SDF. No IS leaders are believed to be in Baghouz, a US defense official said.