MUNICH (AP) — Europeans need to do more than talk if they want to preserve a deal meant to keep Tehran from obtaining a nuclear weapon after the unilateral withdrawal of the United States, Iran's foreign minister said Sunday, slamming Washington as the "biggest source of destabilization" in the Middle East.

Mohammad Javad Zarif told a gathering of world leaders, top defense officials and diplomats that a barter-type system known as INSTEX set up last month by France, Germany and Britain to allow businesses to skirt direct financial transactions with Iran, and thereby evade possible U.S. sancti...