U.S. and Taliban negotiators have broken off after a long round of peace talks with no agreement on when foreign troops might withdraw from Afghanistan, officials from both sides told Reuters. Negotiators talked for 16 days—the U.S. previously said it needed the Taliban to rule out allowing terrorists to use Afghanistan to stage attacks before it could agree to bring an end to the 18-year war. The negotiations in Qatar were led by the Taliban’s political chief, Mullah Abdul Ghani Baradar, and a U.S. team led by special envoy Zalmay Khalilzad. “The conditions for peace have improved. It’s clear all sides want to end the war. Despite ups and downs, we kept things on track and made real strides,” Khalilzad said. The talks are expected to resume in late March.