Iran today announced it is preparing to resume uranium processing, despite warnings from the EU and US that such a move could lead to action by the UN Security Council.
Iran, which insists its atomic programme is for energy production purposes says it may soon re-start uranium processing but has promised to maintain its freeze on actual uranium enrichment, a process which produces bomb-grade fuel.
"We have decided to resume part of our activities in Isfahan [uranium conversion facility]," foreign ministry spokesman Hamid Reza Asefi said.
"We have still not decided which activities and when ... We are at a decision-making stage and whether we reach an agreement [with the EU] or not we will do this," he told a weekly news conference.
Iranian hardliners, who control a majority of seats in Iran's parliament, meanwhile, are threatening to pass a new bill obliging the government to resume uranium enrichment.
Alaeddin Broujerdi, head of parliament's national security and foreign policy commission said the voluntary suspension of Iran's uranium enrichment programme should end.
"The continuation of negotiations with the EU will have no results except the loss of time ... Parliamentarians are very serious about preserving this right for Iran and believe the government should quickly re-start its nuclear programme," he said.
Britain, Germany and France, who are leading the EU's nuclear negotiations with Iran, say a resumption of uranium processing work at Isfahan would violate an agreement struck by the two sides in Paris in November.
Under that agreement, Iran committed to freezing all nuclear fuel manufacture and reprocessing as long as it remained in talks. Iran has said it has not broken off the talks, but is unhappy with the pace of the negotiations and does not believe it is breaking the Paris agreement.
"Our decision to resume part of our activities in Isfahan is fully compatible with the essence of the Paris agreement," Mr Asefi said.
Should Iran recommence uranium processing at Isfahan it would put the EU under heightened pressure from Washington to back its calls for Iran's case to be sent to the UN Security Council for possible sanction.