The UN's nuclear watchdog is considering setting a deadline for Iran to fully comply with its obligations under the international nuclear non-proliferation treaty NPT.
Tehran denies it has a nuclear weapons programme
A draft resolution - drawn up by Britain, France and Germany - is being considered by the board of governors of the International Atomic Energy Agency (IAEA) at a special meeting in Vienna.
It says Iran should "remedy all failures identified by the agency" and "co-operate fully with the [the IAEA] to ensure verification of compliance with Iran's Safeguards Agreement by taking all necessary actions by the end of October 2003".
The draft was released hours after the US said Iran had clearly violated the Safeguards Agreement - part of the NPT which Iran signed in 1970.
"The United States believes that the facts... would fully justify an immediate finding of non-compliance by Iran," US ambassador Kenneth Brill told the board earlier.
But Mr Brill, who serves as ambassador to the UN in Vienna, said Washington had consented to other board member states' desire "to give Iran a last chance to stop its evasions".
The US accuses Iran of trying to develop nuclear weapons and wants the UN agency to condemn it for violating the NPT.
Diplomats at the week-long meeting say a second draft submitted by South Africa does not mention a deadline, the BBC's Bethany Bell reports from Vienna.
The closed-door session of the IAEA's governing board has been examining a report by its inspectors, which says traces of weapons-grade uranium were found at an Iranian nuclear plant.
Iran denies its uranium enrichment activities are part of an illegal weapons programme.
It says it is seeking to produce only low-grade uranium fuel to meet its energy needs.
The draft resolution requests that Tehran provide "a full declaration of the sources and types of all imported material and components relevant to the enrichment programme, especially imported equipment and components stated to have been contaminated with high enriched uranium particles".
It said third countries should "co-operate closely and fully" in determining who supplied Iran with the contaminated uranium.
It says Iran should allow IAEA inspectors free access for "environmental sampling" and resolve questions about gas centrifuges which could be used in enriching uranium.
Earlier, IAEA Director General Mohamed ElBaradei he hoped Tehran would sign up to an additional protocol that would allow intrusive snap inspections of its nuclear facilities.