Straw told the BBC the international community should pursue what he called a patient approach with Tehran. But the minister also said the imposition of UN Security Council sanctions remains a possibility.
French and German officials said any talk of sanctions is "premature."
In Moscow, Russia renewed its call for Iran to resume a moratorium on nuclear activities.
Iran said earlier today it would end voluntary cooperation with the United Nations over its nuclear program if it was referred to the UN Security Council. This week Iran renewed its nuclear research over the objections of the international community.
Iran says it seeks to develop only a civilian nuclear power program in accordance with international law. The West says it suspects Tehran wants to develop an atomic bomb.