Although Foreign Minister Kamal Kharazi asserted that the Islamic republic was committed to a suspension of enrichment itself, he did say "no country has the right to deprive us of nuclear technology."
"We are still continuing with the suspension of enrichment that we agreed to last year" with the European Union's so-called "big three" Britain, France and Germany, Kharazi told reporters.
"During a meeting in Brussels in February, we decided to expand this suspension to making parts for centrifuges. But since the Europeans failed to meet their commitments, we can manufacture centrifuge parts," he said. "We have now started manufacturing centrifuge parts."
Centrifuges are used to enrich uranium. Iran says it only wants to produce fuel for an atomic energy programme, but highly enriched uranium can also be used for nuclear weapons.
Iran denies widespread suspicions it is secretly trying to acquire the bomb.
In October last year Iran signed a deal with the three Europeans to halt certain aspects of its work on the sensitive nuclear fuel cycle as part of building trust with the International Atomic Energy Agency (IAEA).
The October deal covered a suspension of enrichment pending the completion of IAEA inspections. Then in February, Iran agreed to widen the scope of the suspension to related fuel cycle activities.
In return, the three Europeans pledged to help Iran resolve its problems with the IAEA if full cooperation was forthcoming.
But since then experts have found omissions in Iran's reporting, and inspection visits have been delayed.
Judging that Iran had not adequately cooperated, they sponsored a tough resolution critical of the Islamic republic. Iran asserts that it has cooperated, accusing its critics of treating the issue politically and not technically.
Officials from Iran and the three European states have been meeting in Paris over the past two days in what appears to be an effort to salvage the accord -- mostly aimed at "confidence building" while the IAEA probe continues.
But Iranian actions such as resuming centrifuge making, as well as working on other parts of the nuclear fuel cycle, threaten to torpedo the accord.
Diplomats have yet to give any details on how the talks went, although one source close to the negotiations said they were "generally disappointing". He did not elaborate.
The Europeans have been privately pushing for Iran to cease its work on the fuel cycle -- pointing to an inherent weakness in the nuclear Non-Proliferation Treaty (NPT) that allows signatories to master a fuel cycle that could bring them legally within close grasp of a weapons capability.
Iran has refused, and asserts it has no interest in weapons.
On Thursday, US Secretary of State Colin Powell said it was "more and more likely" that Iran's nuclear program would be referred to the UN Security Council as a possible prelude to sanctions.
The United States has accused Iran of wantonly flouting international calls to curb its nuclear activities, saying Tehran is mounting a "direct challenge" to the IAEA.