MOSCOW - Russia says it is working hard to firm up plans for a new round of talks between global powers and Iran over Tehran's nuclear program, which the West suspects is aimed at developing nuclear weapons capability.Iranian news agency ISNA said on Wednesday that Iran and six world powers would resume talks in late January but a European Union official said the two sides had yet to agree a date. No venue has been agreed for the talks, either.But Ryabkov said agreeing a date and venue was ultimately up to the office of EU policy chief Catherine Ashton, who oversees contacts with Iran over its nuclear program on behalf of the United States, Russia, China, France, Britain and Germany.A spokesman for Ashton said in Brussels on Wednesday that no date had yet been set. "Contacts are still ongoing. We are waiting for the Iranians to respond," Michael Mann said when asked about the ISNA report.Western and Russian diplomats had hoped for talks to restart in December or mid-January. Since the last meeting in June, Iran has pressed ahead with disputed nuclear activity and amassed more material that can have both civilian and military purposes.Russia approved four rounds of UN Security Council sanctions against Iran over its nuclear program but opposes new UN sanctions and has sharply criticised separate Western sanctions, saying they are counterproductive.Russia has warned that an Israeli attack on Iranian nuclear facilities would be disastrous and, while Moscow says Tehran must dispel concerns about its nuclear program, it has suggested Western fears about military aims are overblown."Russia is concerned about this and we continue to work, including with our Iranian partners, to resolve this issue as soon as possible," state-run news agency Itar-Tass quoted Russian Deputy Foreign Minister Sergei Ryabkov as saying.Ryabkov, Russia's negotiator at previous rounds of talks that brought no breakthrough, said that until there is a final agreement "there is no agreement".Russia built Iran's first nuclear power plant and has warmer ties with Tehran than the United States and other Western nations do, giving it potential levers to pressure Iran.