The US said Monday it was still ready to meet Iran and was not "dogmatic" about how, after Tehran rejected an EU-proposed gathering.
"We remain ready to engage in meaningful diplomacy to achieve a mutual return to compliance" in a 2015 nuclear deal, State Department spokesman Ned Price said.
President Joe Biden's administration supports a return to the 2015 nuclear accord from which former president Donald Trump withdrew, and on February 18 said it was willing to meet Iran in a meeting proposed by the EU.
The meeting would involve the other signatories of the 2015 agreement – Britain, China, France, Germany and Russia.
But Iran said on Sunday that the timing was not "suitable", as it insisted that the US first lift sanctions imposed by Mr Trump.
"As we have made clear, the United States is prepared to meet Iran to address the way forward on a mutual return to compliance," Mr Price said.
"We're not dogmatic about what form that takes. What we are dogmatic about is the underlying commitment that this administration broadly has: that Iran cannot be allowed to acquire a nuclear weapon."
Iran has insisted that sanctions imposed by Mr Trump, including a sweeping ban on its oil exports, should be removed before it reverses moves it has made away from nuclear compliance.
Pharaoh's curse
British aristocrat Lord Carnarvon, who funded the expedition to find the Tutankhamun tomb, died in a Cairo hotel four months after the crypt was opened.
He had been in poor health for many years after a car crash, and a mosquito bite made worse by a shaving cut led to blood poisoning and pneumonia.
Reports at the time said Lord Carnarvon suffered from “pain as the inflammation affected the nasal passages and eyes”.
Decades later, scientists contended he had died of aspergillosis after inhaling spores of the fungus aspergillus in the tomb, which can lie dormant for months. The fact several others who entered were also found dead withiin a short time led to the myth of the curse.
The story in numbers
18
This is how many recognised sects Lebanon is home to, along with about four million citizens
450,000
More than this many Palestinian refugees are registered with UNRWA in Lebanon, with about 45 per cent of them living in the country’s 12 refugee camps
1.5 million
There are just under 1 million Syrian refugees registered with the UN, although the government puts the figure upwards of 1.5m
73
The percentage of stateless people in Lebanon, who are not of Palestinian origin, born to a Lebanese mother, according to a 2012-2013 study by human rights organisation Frontiers Ruwad Association
18,000
The number of marriages recorded between Lebanese women and foreigners between the years 1995 and 2008, according to a 2009 study backed by the UN Development Programme
77,400
The number of people believed to be affected by the current nationality law, according to the 2009 UN study
4,926
This is how many Lebanese-Palestinian households there were in Lebanon in 2016, according to a census by the Lebanese-Palestinian dialogue committee
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