Iran's Foreign Minister said that Tehran would be able to return to its nuclear activities if the West withdraws from a pact that is to be finalised in June.
Mohammad Javad Zarif, who is also Iran's chief nuclear negotiator, said on a talk show on state-run TV that Iran has the power to take "corresponding action" and "will be able to return" its nuclear programme to the same level if the other side fails to honour the agreement.
"All parties to the agreement can stop their actions [fulfilment of their commitments] in case of violation of the agreement by the other party," Zarif said. He said the deal announced by Iran and six world powers last week in Switzerland was not binding until a final agreement is worked out by a June 30 deadline.
The framework agreement, if finalised, would cut significantly into Iran's bomb-capable nuclear technology while giving Tehran quick access to bank accounts, oil markets and other financial assets blocked by international sanctions.
Zarif said the deal, if finalised, would nullify all UN Security Council resolutions against Iran's nuclear programme and lead to the lifting of US and European Union sanctions.
Zarif's remarks appear aimed at reassuring hardliners in Iran who strongly oppose the framework agreement as a good deal for the West and disaster for Iran.
Despite criticism by hardliners, the deal has been overwhelmingly backed by Iran's establishment, including President Hassan Rouhani who pledged in a speech to the nation at the weekend that Iran will abide by its commitments under the nuclear deal.
Zarif said Iran is committed to implementing its part of any final agreement providing Western countries fulfil their promises.
He said Iran wants to have a "moderate, constructive and proud presence" in the world. In the TV interview, Zarif said he objected to US Secretary of State John Kerry using the word "suspension" rather than "termination" regarding sanctions against Iran in the statement on the framework deal announced in Lausanne, Switzerland.
Zarif attributed Kerry's action as being aimed at addressing rifts between the Obama Administration and Congress over the deal.
Republicans are almost universally opposed to President Barack Obama's diplomatic effort; Democrats remain divided.
The Iran pact
Is the nuclear deal with Iran signed, sealed and delivered?
No. This is the political outline agreement, with technical details still to be filled in by the end of June, so things can still go wrong. But the deal is more detailed than expected on the main points, such as what to do with Iran's uranium enrichment centrifuges, so most participants seem to think the hard part is done.
Doesn't it still have to pass Congress?
The US Congress is threatening to introduce more sanctions, rather than lifting them, which is what Iran is supposed to get out of the deal, so the Republican majority could scupper it. However, it would need a two-thirds majority to over-ride the presidential veto, which would require hawkish Democrats to join the Republicans. The deal is tougher on Iran than expected, so the Obama Administration seems to be confident that it will keep enough Democrats onside. Diplomats believe that the President can use constitutional means to force through the deal over the heads of Congress anyway, but no one in the White House likes talking about taking such action until necessary. A previous outline deal in late 2009 for Iran to ship its enriched uranium out of the country was in fact vetoed by Ayatollah Ali Khamenei, Iran's Supreme Leader. A repeat seems unlikely: negotiators on the UN and EU side assume that their Iranian counterparts have been checking back with Tehran as assiduously as they have with Obama and other political leaders.
Who opposes the deal and why?
Iran's Gulf neighbours, and others with a reason to dislike the country such as Syrian rebels, fear it will empower Iran to throw its weight around. "More money for [Bashar al-]Assad," was one Syrian dissident's succinct summary of the possible lifting of sanctions. Israel believes Iran can break the deal, or at least continue with a nuclear weapons programme which has its research and infrastructure ready for when the most restrictive requirements of the deal expire in 15 years' time. Many American politicians share those fears.
- additional reporting AP