Iran’s Intelligence Ministry said on Wednesday it detained two Europeans as a European Union envoy visits the country over its stalled nuclear negotiations with world powers. The announcement by the ministry, during the visit of EU envoy Enrique Mora, comes as Tehran already is threatening to execute an Iranian-Swedish researcher imprisoned since 2016, and as another Iranian national faces a life sentence in Sweden. Iran long has faced allegations it uses its arrests as a bargaining chip with the West. Tehran denies that, though negotiations around its landmark 2015 nuclear deal saw Americans …