The five major nuclear powers are working on a joint warning statement that aims to show unusual unified resolve and put fresh pressure on Iran not to resume nuclear fuel research, US officials and diplomats said on Friday. Iran, making a confrontation increasingly likely, has defied the international community with its threat to resume on January 9 atomic fuel research and development that was shelved over a year ago at the Westâs insistence.In an effort to bring new pressure in the hours before Tehran takes what could be a fateful step, the United States, Britain, France, Russia and China were working on a statement opposing the Iranian move and urging that Tehran return to negotiations on a compromise proposal, officials and diplomats said. Although the statement, known as a demarche, is not expected to contain specific threats, such as bringing Iran to the UN Security Council where sanctions could be imposed, officials said that it could have significant political impact. âItâs another ratchet upward in terms of diplomatic pressureâ because it is the first coordinated initiative on Iran by the five nuclear weapon states and would âshow unity and cohesion among the P5, which has not always been there,â said one US official.