International sanctions could be reimposed on Iran if it reneges on commitments under its nuclear deal, sources at the French presidency said on Tuesday, after Tehran said it would scale back its compliance a year after Washington pulled out.
Iran dismissed a U.S. announcement of the deployment of an aircraft carrier to the Middle East as old news, recycled for psychological warfare, and said it would soon announce plans to roll back some of its commitments under the 2015 deal.
Tensions have risen on the eve of the anniversary of President Donald Trump's withdrawal from the agreement, under which Iran agreed to curbs on its nuclear programme in return for the lifting of international sanctions.
The Trump administration has restored U.S. sanctions and extended them, effectively ordering countries around the world to stop buying Iranian oil or face sanctions of their own.
Iran has continued complying with the deal. Washington's European allies, which oppose the U.S. pull-out, have tried and failed to come up with ways to blunt the economic impact of the U.S. move while urging Iran to continue to comply.
Iranian media reported that Tehran will write to the countries still signed up to the deal -- U.S. allies Britain, France and Germany as well as Russia and China -- on Wednesday to give them details about plans to "diminish its commitments" under the deal.
Iranian state news reports have said Iran does not plan to pull out, but will revive some nuclear activity that was halted under the deal.
A French presidential source said the European countries did not yet know precisely what steps Iran was now planning, but they could have to reimpose sanctions on Iran if those steps amount to reneging.
"We do not want Tehran to announce tomorrow actions that would violate the nuclear agreement, because in this case we Europeans would be obliged to reimpose sanctions as per the terms of the agreement," the source said.
"We sent messages to Tehran to say that we were determined to implement the agreement, that we really wanted them to stay in this agreement even though we took into account the complexity of the situation and passed on the same messages to our American allies," the source said.
A second French official later said that if Tehran failed to comply with the deal, the issue would be treated through a dispute mechanism under the accord itself, which could lead to the reimposition of UN Security Council sanctions.
U.S. officials have spoken in recent days of intelligence suggesting a military threat from Iran, although they have not given specific details.
U.S. national security adviser John Bolton said on Sunday the United States was deploying the Abraham Lincoln carrier strike group and a bomber task force to the Middle East in a warning over threats by Iranian forces.
But Keyvan Khosravi, spokesman for Iran's Supreme National Security Council, said the Abraham Lincoln was already due in the Gulf and dismissed the announcement as a "clumsy" attempt to recycle old news for "psychological warfare".
The United States typically rotates an aircraft carrier in the Gulf to serve as the flagship of its Fifth Fleet based in Bahrain. The previous carrier in the area, the John C Stennis, left in April to sail for home at the end of its deployment.
Acting U.S. Defense Secretary Patrick Shanahan said on Monday he had approved dispatching the carrier strike group and bombers due to indications of a "credible threat by Iranian regime forces". He gave no details of underlying intelligence.
Iranian Foreign Minister Mohammad Javad Zarif said on Twitter: "If U.S. and clients don't feel safe, it's because they're despised by the people of the region - blaming Iran won't reverse that."
Iran's state-run Press TV earlier said: "The deployment seems to be a 'regularly scheduled' one by the U.S. Navy, and Bolton has just tried to talk it up."
A military adviser to Supreme Leader Ayatollah Ali Khamenei said the United States was "neither willing nor capable" of military action against Iran, the semi-official news agency ISNA reported.
Unnerved by the war of words, Iran's rial currency extended its fall on Tuesday, hovering around a seven-month low of 150,500 against the dollar on the unofficial market, foreign exchange websites reported.
Since withdrawing from the nuclear deal, Washington has given waivers to some countries, mainly in Asia, to keep buying Iranian oil for a limited time. But last week it said it would now end the waivers to reduce Iran's crude exports to zero.
The administration also blacklisted Iran's elite Revolutionary Guard Corps as terrorists. The Guards control a large swathe of Iranian industry, so their blacklisting could make it harder for foreign companies to do business with Iran.
Iran has responded by declaring all U.S. forces in the Middle East to be terrorists. It has also made threats to close the strategic Strait of Hormuz in the Gulf if Tehran were barred from using it. Around 30 percent of the world's seaborne oil exports pass through the strait.
While neither Shanahan nor Bolton elaborated on the gist of U.S. intelligence, other U.S. officials told Reuters there were "multiple, credible threats" against U.S. forces on land, including in Iraq, by Iran and proxy forces, and at sea.