LAUSANNE, Switzerland (AP) — Iran nuclear negotiators resumed talks here Wednesday, just hours after abandoning a March 31 deadline to reach the outline of a deal and agreeing to press on. However, as the discussions dragged on, three of the six foreign ministers involved left the talks, and prospects for agreement remained uncertain. Claiming enough progress had been made to warrant an extension after six days of intense bartering and eager to avoid a collapse in the discussions, U.S.