Efforts to reach a political agreement on Iran’s nuclear program by the end of the month intensified on Tuesday as negotiations between the United States and Iran resumed, and Western officials warned that tough issues remained unresolved. The U.S. and Iranian delegations led by U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif began another round of talks in the Swiss city of Lausanne after the Iranians returned overnight from Brussels where they had met European foreign ministers. Senior European officials were expected in Lausanne later on Tuesday, with foreign ministers possibly joining them at the end of the week if talks advance. A Western diplomat said “we’re still not there yet” on reaching an end-March deadline for a framework agreement between Iran and six major powers — the United States, Britain, France, Germany, Russia and China. “We’ll see what happens […]