Islamic State (IS, formerly ISIS) is down to its last few hundred fighters and less than a square kilometer of land in a battle for its last Syrian stronghold, US envoy James Jeffrey said on Friday. However, IS may have 15,000-20,000 adherents in Syria and Iraq, according to Jeffrey. “We are just about finished with the campaign along the Euphrates to defeat the last territorial holdings of the caliphate,” said Jeffrey, who is the US special representative for Syria engagement and special envoy to the global coalition to defeat IS. He said the struggle to defeat IS’ ideology would go on and there was no timetable for a US withdrawal, Reuters reports.