(Adds army statement on arrests) BEIRUT, Oct 28 (Reuters) - Leba**n is negotiating with Sunni militants to prevent the killing of two captured soldiers, the country's health minister told Reuters on Tuesday. Wael Abu Faour would **t say which group he was talking with but both Islamic State and al Qaeda's Syria wing, the Nusra Front, have captured Lebanese soldiers. Three have been killed. "We received a specific request from the kidnappers in exchange for halting the execution of the soldiers ... Matters are going in a positive direction," he said, without giving details on the demand. ...