“We can confirm that we have received the response from Iran through the European Union,” said Vedant Patel, deputy spokesman for the State Department. “We are studying it, and will respond through the European Union, but unfortunately it is not constructive,” he added.

The head of European diplomacy Josep Borrell had however said on Wednesday that he hoped for an agreement “in the days to come”.

The EU presented on August 8 what it called a final text to restore the historic 2015 agreement, which had been buried by former US President Donald Trump.

Iran proposed changes to it – generally accepted by the Europeans – and to which the United States responded via the mediators.

Iranian Foreign Ministry spokesman Nasser Karani said earlier on Thursday that Tehran had sent a new response after that of the United States, according to Iran’s official Irna news agency.

Negotiations on Iranian nuclear power, which began 16 months ago but which had been suspended and then resumed in early August, aim to relaunch this agreement concluded in 2015 with Tehran by the five permanent members of the UN Security Council (China, USA, France, UK and Russia) plus Germany.

– Easing of sanctions –

Joe Biden has long promised to restore the deal, saying it was the best way to limit Iran’s nuclear program, and that the US withdrawal had only prompted Tehran to accelerate its project.

Under the new proposal, Iran would receive sanctions relief and could once again sell its oil in exchange for tight restrictions on its nuclear program.

Iran and the United States responded by proposing a series of changes. But according to Washington, Tehran’s response is insufficient.

During an interview on Wednesday with Israeli Prime Minister Yair Lapid, a fierce opponent of the agreement, Joe Biden had “underlined the commitment of the United States never to allow Iran to acquire nuclear weapons” .

Washington assures that Iran has made crucial concessions, and in particular has abandoned its request to block certain inspections by the IAEA, the International Atomic Energy Agency.

This subject of inspections remains however ultra-sensitive on both sides.

Tehran thus recently requested the closing of an investigation by the IAEA concerning traces of enriched uranium found on three undeclared sites, which the head of the Agency, Rafael Grossi, refuses.

The UN nuclear policeman had deplored the lack of “credible” answers from Tehran concerning these traces.