PROVIDENCE (AP) — A federal mediation agency today indefinitely postponed an announcement of a proposed settlement of a legal challenge to Rhode Island’s landmark 2011 pension overhaul, leading to questions about the status of the deal.The Federal Mediation and Conciliation Service had scheduled a news conference for this afternoon to announce the settlement, but it said shortly before 5:30 a.m. that the event had been postponed at the request of lawyers for the state and state employee unions and retirees.The only reason given for canceling the event was that the parties were continuing to talk and work with federal mediators.“The parties remain under the court-mandated confidentiality order. Further updates as to scheduling will be available through FMCS, when appropriate,” the mediation agency said in a statement.Spokeswomen for Gov. Lincoln Chafee and Treasurer Gina Raimondo said they couldn’t comment about the negotiations or the announcement being postponed because of a court-imposed gag order.The board of the state’s Employees’ Retirement System was still scheduled to meet this morning. It had been scheduled to discuss behind closed doors and possibly vote on what its agenda calls a proposed settlement in the case. It was unclear whether that discussion would still happen.Word emerged Monday of the proposed settlement to end the legal challenge to the state pension overhaul. No details were released publicly, but the governor and general treasurer briefed legislative leaders that afternoon.The General Assembly must approve any deal. Messages left this morning for spokesmen for House Speaker Gordon Fox and Senate President Teresa Paiva Weed were not immediately returned.Rhode Island had one of the worst-funded pension systems in the nation before legislators passed the 2011 law, which raised retirement ages, suspended pension increases and made other changes to save billions of dollars in future pension costs. It has served as a model for lawmakers in other states looking to rein in their pension systems.Public-sector unions and retirees argued the changes were unfair and sued to block the law. The lawsuit has been the subject of closed-door mediation since 2012. The legal fight has been closely watched by unions, state officials and financial analysts around the country.Any deal could significantly change the state’s public retirement system and increase pension costs by millions of dollars every year. Lawmakers have expressed frustration about how the fate of the law — passed after months of public hearings and debates — was being decided in closed-door negotiations.