The United States, in a message aimed at Russia, called on governments involved in nuclear projects in Iran to immediately freeze those projects.
Stephen Rademaker, the US assistant secretary of State for arms control, said governments should adjust their national policies following last month's finding by the International Atomic Energy Agency that Iran should be reported to the UN Security Council because it failed convince the international community that its nuclear program was entirely peaceful.
"We think it is self-evident, for example, that in the face of such a finding, no government should permit new nuclear transfers to Iran, and all ongoing nuclear projects should be frozen," Mr Rademaker told the UN General Assembly's disarmament committee.
Although he did not mention Russia by name, Moscow is building a $1 billion civilian nuclear reactor at Bushehr in Iran and has agreed to supply it with fuel.