Iranian President Mahmoud Ahmadinejad has tasked the country's atomic chief with enriching uranium to 20 percent, in order to meet the demands of the country's cancer patients.

Speaking at the exhibition of Laser Science and Technology Achievements in Tehran, the president called on Ali Akbar Salehi, to start the process.

"Mr. Salehi you start enriching up to 20 percent and we are still open to negotiations on the issue," he told the head of the country's atomic energy organization who was sitting in the audience.

Thousands of Iranian patients, in need of post-surgery drug treatment with nuclear medicine, will suffer if domestic production dries up when a research reactor in Tehran runs out of fuel.

The Tehran research reactor, which produces 20 different kinds of radio-medicine for cancer patients, runs on uranium that is some 20 percent U-235 — an enrichment level higher than what is currently produced at Iran's Natanz enrichment facility.

Iran has requested the International Atomic Energy Agency to arrange for supplying of the fuel to the country. The West has been pressuring Iran to accept a UN-backed draft deal which requires Iran to send most of its domestically-produced low enriched uranium (LEU) abroad for conversion into the more refined fuel that the Tehran reactor requires to produce medical isotopes.

Iran says its concerns over the proposal, which was first floated by the US, should be heeded.

The development comes as Tehran has been trying to find a middle ground with the West over the nuclear swap.

Iranian Foreign Minister Manouchehr Mottaki expressed hope on Saturday that an agreement on the nuclear fuel proposal will soon be reached with the Western side, but with the changes that Tehran seeks.

His remarks were largely ignored by US Defense Secretary Robert Gates who has instead insisted on the imposition of fresh sanctions on the country.