Iran is ready to exchange the bulk of its stockpile of enriched uranium for nuclear fuel rods - as proposed by the U.N. -  but according to its own mechanisms and timetable, the foreign minister said Saturday.

The minister's remarks come just days before an expected meeting between the U.S. and allies to discuss new sanctions against Iran over its nuclear program. The offer, however, falls far short of the conditions set by the international community.

Speaking to reporters at a regional security conference in Bahrain, Manochehr Mottaki said Iran agreed with a U.N. deal proposed in October in which up to 1,200 kilograms of its uranium would be exchanged for fuel rods to power its research reactor.

“We accepted the proposal in principle,” he said through a translator. “We suggested in the first phase we give you 400 kilograms of 3.5 per cent enriched uranium and you give us the equivalent in 20 per cent uranium.”

Iran has about 1,500 kilograms of low-enriched uranium and needs to refine to 20 per cent to operate a research reactor that produces medical isotopes.

Uranium enriched at low levels can be used as fuel for nuclear energy, but when enriched to 90 per cent and above, it can be used as material for a weapon. The United States and five other world powers have been trying to win Iran's acceptance of a deal under which Tehran would ship most of its low-enriched uranium stockpile abroad to be processed into fuel rods, which can't be enriched further.