France, Britain and Germany cannot continue talks with Iran unless it promises not to begin enriching uranium, German Deputy Foreign Minister Gernot Erler said on Wednesday. He said Iran's removal of U.N. seals and its announcement that it would resume research on uranium enrichment, a process that can produce fuel for atomic energy or weapons, violated a 2004 agreement in which Tehran pledged to freeze all enrichment-related work. "There can be no further negotiations without a guarantee from Iran that it will not conduct any activities related to (uranium) enrichment," Erler told German radio. The foreign ministers of France, Britain and Germany and EU foreign policy chief Javier Solana will meet in Berlin on Thursday to discuss the escalating crisis over Iran's atomic fuel programme, which Tehran says is intended to fuel power plants.