Iranian Foreign Minister Mohammad Javad Zarif on Tuesday denied US claims that the Islamic republic had scuttled nuclear talks in Geneva, pointing instead to France as the culprit.
US Secretary of State John Kerry said in Abu Dhabi on Monday Iran had balked at the Geneva talks just as world powers were closing in on a deal to curb Tehran's nuclear programme in return for sanctions relief.
"The P5+1 was unified on Saturday when we presented our proposal to the Iranians... But Iran couldn't take it," said Kerry, who took part in the high-level talks.
Zarif, on his Twitter account, alluded to comments by French Foreign Minister Laurent Fabius, who has been pilloried in the Iranian media after reports emerged that he scuppered a potential deal.
"Mister Secretary of State, is it Iran which changed half the text of the Americans on Thursday and made contrary statements on Friday morning?" Zarif asked.
Late Monday, Zarif, played down Kerry's remarks.
"If we want to be fair, sometimes these comments are made to address certain concerns, or those of the hosting country," the foreign minister said.
Fabius joined the talks on Friday and immediately issued a statement saying that while there had been progress in the talks, "nothing has been agreed yet".
The following day he was even less upbeat.
"There is an initial draft that we do not accept," Fabius told France Inter radio Saturday morning.
"There are some points on which we are not satisfied," he added, citing the "extremely prolific" Arak nuclear reactor and the question of uranium enrichment.
The talks, which saw the foreign ministers of the P5+1 group -- Britain, France, the United States, Russia and China plus Germany -- rush to Geneva in hopes of finally concluding a deal with Iran, ended inconclusively early on Sunday.
They will resume in Geneva on 20 November.
Diplomats insist a deal is close despite the lack of breakthrough at the weekend.