Iran's parliament has threatened to force a withdrawal from the nuclear Non-Proliferation Treaty if the current row over Tehran's controversial nuclear programme is not resolved through talks.
A withdrawal from the Non-Proliferation Treaty would mean the country's programme could not be inspected by the International Atomic Energy Agency.
The threat - in a letter to United Nations Secretary General Kofi Annan - came a day before a meeting in New York of foreign ministers from the five permanent members of the UN Security Council.
An informal meeting of the security council to discuss a draft resolution on Iran's nuclear programme failed to reach an agreement over the weekend.
Russia and China refused to back the draft text unless major changes are made to it.
The US ambassador to the UN, John Bolton, said no action would be taken without going back to the UN.
