Foreign ministers from six world powers are to meet in London on Friday to discuss Iran's nuclear ambitions, with the United States, backed by Britain, suggesting it is time to consider sanctions against Tehran. But Russia and China could signal their opposition to sanctions while some European countries also say diplomacy must be given more time. Iran on Thursday repeated that it would not stop uranium enrichment. Its government says the program is only for power generation. Apart from Germany, the countries meeting in London are the veto-wielding United Nations Security Council members. U.S. Secretary of State Condoleezza Rice was due to travel from Iraq to London for the meeting, according to State Department spokesman Sean McCormack. "Certainly I expect that discussions of how to proceed, in terms of a sanctions resolution, as called for under Security Council Resolution 1696, would be part of that discussion," U.S. State Department spokesman Tom Casey told CNN. Casey noted that European Union foreign policy chief Javier Solana had signaled his discussions with Iranian nuclear negotiators "are drawing to an end." "It's clear that we don't have a positive response from the Iranians to the offer that's been made to them." Casey said. "As we've always said, the next step then is to proceed with a sanctions resolution" under Chapter 7 of the United Nations charter. While Casey declined to offer a concrete timeline for such a resolution, he said the time "has drawn pretty near." Rice, British Foreign Secretary Margaret Beckett and representatives from France, Germany, Russia and China will gather for the talks from 5 p.m.