Iran said Sunday that it would resume activities at one of its nuclear sites, but said it would keep its freeze on a more advanced process needed to make fuel or weapons. The European Union, which has been seeking to negotiate an exit to the Iranian nuclear impasse, responded by saying Iran would jeopardize future talks if it carried through on its threat, risking a significant worsening of the dispute over its nuclear facilities. Hamidreza Assefi, Iran’s Foreign Ministry spokesman, said Iran planned to tell the International Atomic Energy Agency in Vienna in a letter of its decision to restart work at the Uranium Conversion Facility in Isfahan. The Iranian news agency quoted Mr. Assefi as saying Iran had taken the step because the European Union had failed to meet a deadline to produce new proposals to end the impasse. Full Story