Calls mount to avert 'massacre' in Syria's Idlib

International calls mounted Wednesday to avoid a "massacre" by regime forces in Syria's last rebel-held province of Idlib, two days before a summit between key powers backing the government and opposition.Troops have been massing on the edges of the northwestern province which borders Turkey for weeks, raising fears of a humanitarian disaster on a scale not yet seen in Syria's seven-year conflict.The United States on Wednesday warned an all-out offensive in Idlib would be a "reckless escalation"