UN Secretary General Ban Ki-Moon urged Iran on Wednesday to resume talks with the six international mediators over its controversial nuclear program.

The statement came following media reports that quoted a Western diplomat as saying representatives of the Iran Six - Russia, the U.S., China, Britain, France, and Germany - had discussed possible new sanctions against the Islamic republic during telephone talks on Wednesday.

The diplomat said however that the six mediators had failed to reach an agreement over the issue, mainly due to China''s position. Beijing has repeatedly opposed sanctions against Iran, which is suspected by Western powers of attempting to build nuclear weapons under the guise of peaceful power generation. Iran says it needs the program for the generation of civilian energy.

"All member states of international community have deep concern on the nuclear development program," Ban said.

"Iran should return to negotiations," he said, adding "I again urge that this issue should be resolved peacefully through dialogue as soon as possible."

Under a plan drawn up by the IAEA last October, Iran was to ship out its low-enriched uranium to Russia, where it would be enriched and then sent to France to be made into fuel rods and returned to the Islamic Republic for use in its research reactor in Tehran.

But the proposal was then rejected by Tehran, which suggested it could consider a simultaneous swap of its low-enriched uranium for 20%-enriched uranium, but that the exchange would have to take place on its own territory.