Iranian Foreign Minister Manouchehr Mottaki said on Monday that the UN Security Council should not be used by "some countries" to put pressure on Iran.
"We believe the time of threats is over," Mottaki said after meeting with Belgian Foreign Minister Karel De Gucht.
"The Security Council of the United Nations should not be considered as a tool in the hands of some countries," he said.
He was speaking amid fresh diplomatic efforts to defuse the crisis.
The Iranian negotiating team was in talks in Russia about a compromise proposal to enrich uranium on Russian territory.
Iran maintains that it only wants to generate electricty with its nuclear programme.
Some of its activities have raised concerns in the West that it is trying to develop an atomic weapon.