Iran planned to hold a call with three European nations Friday as they threatened to reimpose United Nations sanctions on Tehran over its nuclear program. The call Iran will hold with France, Germany and the United Kingdom comes as Tehran faces an Aug. 31 deadline set by the three nations to reach a “satisfactory solution” to the nuclear issues. The call is just the latest moment in the fraught relations Iran has with the West over its atomic program, which has been enriching uranium close to weapons-grade levels.