Federal energy regulators say the merger of Duke Energy and Progress Energy to create the country's largest electric company must include sweeping changes to protect competition in the Carolinas.

Duke Energy spokesman Tom Williams said Sunday the company is evaluating the order issued by the Federal Energy Regulatory Commission late Friday.

Federal regulators conditionally approved Charlotte-based Duke Energy's purchase of Raleigh-based Progress Energy, but told the two electric companies to propose solutions within 60 days that would protect competition in North Carolina and South Carolina.

The agency suggested that remedies could include selling off power plants, building new transmission lines or joining a regional transmission authority.

The federal order was first reported Sunday by the News and Observer of Raleigh.