A meeting between Iran's top diplomats and world powers due on Thursday at the United Nations will start a "new era" in efforts to end the dispute with the West over Tehran's disputed nuclear program, the Iranian Foreign Ministry said on Tuesday.
It did not hint at any concessions by Tehran.
The European Union said on Monday Iranian Foreign Minister Javad Zarif would join a meeting of major powers -- including Britain, France, China, Russia and the United States and Germany -- to discuss the Iranian nuclear programme.
The meeting, expected to include US Secretary of State John Kerry, would be the highest-level encounter involving the two nations since relations were severed in 1980 at the height of the US Embassy hostage crisis.
"These talks are the start of a new era. The Islamic Republic has explicitly stated its views regarding its rights to peaceful nuclear energy and the right to enrich (uranium) on Iranian territory," Foreign Ministry spokeswoman Marzieh Afkham told a news conference, Mehr news agency reported.
"This meeting represents a serious commitment of the foreign parties to reach a solution based on a specified time-frame."
Before leaving for New York on Monday, newly-elected President Hassan Rouhani said he wanted to present Iran's "true face" and to pursue talks and cooperation with the West to end the nuclear dispute.
Iran says it is enriching uranium only to fuel a planned network of nuclear power stations, and for medical purposes.
The United States and its allies have imposed tough economic sanctions on Iran over suspicions that it is seeking a nuclear weapons capability.
Refined uranium can provide the fissile material for nuclear bombs if processed further, which the West fears may be Tehran's ultimate goal given that Tehran has a history of hiding some nuclear activity from UN anti-proliferation inspectors.
US officials have also said a meeting is possible this week between President Barack Obama and Rouhani, who are both due to address the General Assembly on Tuesday.
But on Tuesday, Afkham appeared to play down this possibility, telling reporters: "No programme has been organised for a meeting and it is rather (a) discussion in the media."