VIENNA, June 2: The United States said on Wednesday that Iran continues to cover up a nuclear weapons programme and that the latest report by the UN atomic watchdog had only made this more apparent.

"I think that this persistent refusal to fully cooperate (with UN inspectors) fits a long-term pattern of denial and deception that can only be designed to mask Iran's military nuclear programme," the US ambassador to the UN in Vienna, Kenneth Brill, told reporters.

The United States accuses Iran of running a secret nuclear weapons programme that is parallel to its declared atomic energy programme. Iran denies this, insisting its ambitions are limited to the peaceful generation of electricity.

The International Atomic Energy Agency (IAEA) said on Tuesday in a confidential report on Iran there were two major issues it must resolve. First is the origin of enriched uranium traces found at sites in Iran, which some diplomats on the IAEA board say had raised concerns Tehran was secretly enriching uranium for use in weapons.

The second is Iran's centrifuge programme, especially its interest in advanced P2 enrichment centrifuges capable of making bomb-grade uranium. The report said Iran had admitted importing P2 parts and may have had interest in parts for thousands of centrifuges - contrary to what it had previously said.

"Unanswered questions continue to be the hallmark of Iranian cooperation with the (IAEA)," Mr Brill said. "The more the IAEA digs, the more problems it finds. It is equally clear that the IAEA is not buying Iranian explanations on the key questions and that the list of outstanding issues is larger than it was in March," he said.

The IAEA issued its last report on Iran in March. One of the most controversial issues in that report was the discovery of previously undeclared research on the P2 centrifuges.

The IAEA board begins meeting on June 14 to discuss the new report. The United States is expected to push hard for a resolution condemning Tehran's less-than-total cooperation, though it is unlikely to push for a report to the UN Security Council for possible sanctions, Western diplomats said. -Reuters