"We assume further reductions in Iran's already insufficient cooperation would likely lead to additional IAEA reports of additional Iranian non-compliance," spokesman Gonzalo Gallegos said.

"It's hard to see how such a downward spiral is in the interests of the Iranian people," he said.

"We hope, therefore, that the Iranian regime (government) will set aside threats and confrontation and begin immediately the cooperation the Security Council has made a requirement."

Gallegos made the remarks after Iran's parliament passed earlier in the day a bill urging the government to "accelerate" Iran's controversial nuclear program and to reduce its cooperation with the IAEA in an reaction to the UN sanctions imposed on Tehran.

The UN Security Council adopted unanimously Resolution 1737 on Saturday, demanding Iran "suspend all enrichment-related and reprocessing activities, including research and developments on all heavy water-related projects."

The resolution also called on all states to impose a ban on trade with Iran in goods related to its nuclear programs and ballistic missile delivery systems.

"All states shall freeze the funds, other financial assets and economic resources" owned or controlled by officials and companies in the country's nuclear and missile programs, the UN resolution said.

Iran, which refuses to heed the UN Security Council's demand to suspend uranium enrichment, lashed out at the resolution as an "illegal measure."