ENLARGE U.S. Secretary of State John Kerry and Iranian Foreign Minister Javad Zarif in Geneva last week. Associated Press BRUSSELS—Nuclear talks between Iran and six powers over Tehran’s nuclear program will resume at senior-official level early next month, a spokeswoman for the European Union said Monday. She said talks in Geneva on Sunday between the parties were “serious and useful” and they had decided to meet again in early February. Others, however, said the talks remain very difficult. The EU chairs the six-power group—made up of the U.S., Russia, China, France, the U.K. and Germany—which negotiates on the nuclear dossier. U.S. Secretary of State John Kerry held talks on Wednesday and on Friday with his Iranian counterpart, Javad Zarif, in an effort to accelerate the diplomacy. Senior U.S. diplomats also held several days of meetings in Geneva over the weekend with Iranian negotiators. The two sides have set a […]