Iran's Atomic Energy Organization said on Tuesday it had no information about the illicit procurement of equipment for the Arak research reactor as alleged in a report by a UN panel of experts and based on a briefing by a member country.
The panel, which monitors compliance with the UN's Iran sanctions regime, said in a report seen by Reuters on Monday that Tehran's illicit procurement of banned nuclear technology appeared to have continued in breach of sanctions.
The panel said it was briefed by a member state, which several diplomats identified as the United States, that it "had observed no recent downturn in procurement by Iran".
The state in question had noted a "relative decrease in centrifuge-related procurement" but "an increase in procurement on behalf" of the Arak reactor, the report said.
Iran's Atomic Energy Organization spokesman, Behrouz Kamalvandi, told the semi-official Fars news agency: "I don't have any information on this issue."
Kamalvandi did not address whether such procurement activity violated UN sanctions. However, he did say it was not a breach of last year's nuclear agreement, since "only bans installing new equipment in the (Arak) reactor, not buying new parts."
Under last year's interim deal signed in Geneva between Iran and world powers, the Islamic Republic agreed not to make any further advances to its construction work at Arak.
The unfinished Arak reactor has long been a concern for the United States and its allies as such a reactor type can yield plutonium for bombs. Iran says it is only intended for medical and agricultural research.
The International Atomic Energy Agency, which monitors the implementation of the agreement, confirmed last month that Tehran is far from meeting its commitments under the accord.
The future of the Arak plant is one of several issues Iran and the powers need to settle as part of a comprehensive resolution of a 12-year dispute over Iran's nuclear program.
Western and Iranian officials say they do not expect Arak to turn into a deal-breaker, and that there are various options on the table.
The negotiations on a long-term deal were extended by seven months after the sides failed to meet a Nov. 24 deadline for a settlement. The main sticking point is the size of Iran's uranium enrichment capacity.