Lebanon emerged as the central flashpoint during the latest U.S.-Iran talks in Switzerland, with Iranian negotiators warning that broader diplomatic progress cannot move forward unless fighting on the Lebanon front ends. Tehran reportedly made clear that implementation of any future agreement depends on developments in Lebanon, while Israeli leaders insisted IDF forces will remain deployed despite mounting international pressure. The dispute has become the biggest obstacle to a wider breakthrough, as regional powers including Turkey warn that unresolved tensions could still derail the fragile peace process.