Pressure deepened against Iran on Thursday when the world's eight top economic powers gave Teheran until year's end to cease enriching uranium or face new sanctions, but resistance from China could undermine the effort. Washington has been pushing for heavier sanctions if Iran does not agree to end enrichment, which many nations believe is part of Teheran's drive to build a nuclear weapon. Iran says its nuclear program is designed to generate electricity. The US hand was strengthened Wednesday when Russian President Dmitry Medvedev suggested he could now back such sanctions if they became necessary. But, the prospects of pushing a new sanctions resolution through the Security Council were undercut Thursday when China, one of the veto-wielding permanent members, rejected the idea. Instead, more diplomatic efforts are needed, Chinese Foreign Ministry spokeswoman Jiang Yu told reporters in Beijing at a news conference, reiterating a long-held stance. Current UN sanctions on Iran are meant to prohibit exports of sensitive nuclear material and technology. They also allow the inspection of cargo suspected of carrying prohibited goods, tighter monitoring of financial institutions and the extension of travel bans and asset freezes if linked to its nuclear program. Iranian President Mahmoud Ahmadinejad, in his Wednesday speech to the General Assembly, did not mention the nuclear matters issue and the push by the US, Britain and France for heavier sanctions. On Thursday, Italian Foreign Minister Franco Frattini said the Group of Eight nations has given Iran until the end of the year to commit to ending uranium enrichment if it wants to avoid new sanctions. Frattini, who's nation holds the rotating chair of the club of wealthy nations known as the G-8, said that member foreign ministers agreed Wednesday night "to give Iran a chance." But Frattini said that the informal agreement will be re-examined each month, "And after the end of December, I strongly hope we will have at that time practical moves from Iran." "That's why together we decided - while not excluding further measures, as even Russia apparently said -- we have to give Iran a serious chance," he said. "If we give a chance, let's give a chance. Don't, I would say, immediately put another option on the table. This would be counterproductive to the eyes of our counterpart. This is our strategy for the moment." The maneuvering comes ahead an Oct. 1 meeting of diplomats from Iran, the US, Britain, France, Russia, China and Germany on Teheran's nuclear program. The key to new sanctions would require agreement among all five permanent Security Council members. The United States, Britain and France lean toward more sanctions. Russia now appears open to the measure, but China still is refusing. Beijing is heavily reliant on Iranian oil imports. "We believe we need to help Iran to take a right decision," Medvedev said Wednesday night after he met President Barack Obama on the sidelines of the UN General Assembly. The US, Britain and France all mentioned Iran, along with North Korea, as obstacles to a safer world during a Security Council meeting Thursday that approved a US-drafted resolution that commits all nations to achieving a nuclear weapons-free world. The resolution does not mention any country by name but it reaffirms previous resolutions that imposed sanctions on Iran and North Korea for their nuclear activities. It did not call for any new sanctions. Since Iran's nuclear program was discovered seven years ago, it has put thousands of centrifuges online to churn out enriched uranium. But the International Atomic Energy Agency says the more than a ton of enriched material it has amassed is all below the 5 percent level and well below the 20 percent highly enriched mark. Still Iran's accumulation of well over 1,000 kilograms (2,200 pounds) of low-enriched uranium gives it more than enough material to produce enough weapons-grade uranium through further enrichment for one nuclear weapon.