A deal to grant Turks visa-free travel to most of the European Union was hanging by a thread Thursday after President Recep Tayyip Erdogan defiantly vowed Ankara would not fulfil a key condition set by Brussels. With alarm growing over the deal’s future, European Commission chief Jean-Claude Juncker bluntly told Erdogan that Turks would only enjoy travel to the passport-free Schengen area if all conditions were met and it would be “his problem” if this failed to materialise. The promise of visa-free travel is a key pillar of the landmark March accord for Turkey to stem the flow of migrants to the EU and this could now also be in peril.