Washington says Iran plans to use enriched uranium to make nuclear weapons, but Tehran says its nuclear program is dedicated solely to generating electricity.

The U.N. International Atomic Energy Agency (IAEA), the U.N. nuclear watchdog, unanimously adopted a resolution on Saturday calling on Iran to suspend all uranium enrichment-related activities.

"Iran will not accept any obligation regarding the suspension of uranium enrichment," chief nuclear negotiator Hassan Rohani told a news conference on Sunday. "No international body can force Iran to do so."

His words chimed with the view of the Iranian parliament, which urged the government to ignore the resolution.

Rohani predicted a rough ride in the weeks ahead, until the next IAEA board of governors meeting on November 25.

"This is a war, we may win or we may lose," said the mid-ranking cleric, who is secretary-general of Iran's Supreme National Security Council.

Although the IAEA board termed the suspension a "necessary" confidence-building measure, it observed that any suspensions would be "voluntary decisions" for Iran and not obligations.

This would give Iran some room for maneuver, enabling it to suspend enrichment activities but tell its domestic audience it was not doing so under pressure from the U.N. watchdog.

"Iran has never accepted suspension through a resolution, but through political talks," Rohani said.

END SNAP CHECKS Rohani said Iran would stop allowing U.N. inspectors to make short-notice visits to its atomic facilities if the Islamic Republic's dossier were sent to the U.N. Security Council for possible sanctions.

"If they want to send Iran to the Security Council, it is not wise, and we will stop implementing the Additional Protocol," he said.

The Additional Protocol to the nuclear Non-Proliferation Treaty (NPT) allows U.N. inspectors to make snap checks of nuclear facilities. Iran is implementing its terms, though parliament has not ratified it.

Rohani also said Iran could pull out of the NPT if the Security Council took extreme measures against it. "If they impose economic sanctions, parliament may ask the government to pull out of the NPT," he said.

Iran agreed to suspend uranium enrichment-related activities last year after talks in Tehran with foreign ministers from France, Britain and Germany, the so-called EU big three.

But in July Iran said it had restarted building centrifuges and had recommenced work at a plant that produces uranium hexafluoride, the gas pumped into centrifuges. Centrifuges enrich uranium by spinning it at supersonic speeds.

Enriched to a low level, uranium can be used to fuel nuclear power stations like the one Iran is building at Bushehr on its south coast. If further enriched, it can be used in warheads.

Iran says that while it has restarted enrichment-related activities, it has not restarted enrichment itself.

But it says last year's suspension was agreed with the EU 'big three' on a goodwill basis which allows it to resume the process whenever it wants.