The five United Nations veto powers and Germany failed to agree on an initial nuclear deal with Iran, European Union foreign policy chief Catherine Ashton said after three days of talks concluded early Sunday, dpa reported.
"A lot of concrete progress has been made, but some differences remain," she said chief negotiator of the group of Britain, China, France, Russia, the United States and Germany.
Senior officials from involved countries would meet again November 20 in Geneva to try and clinch a deal, Ashton said.