Iran’s Supreme Leader has warned his country will not step back “one iota” from its nuclear rights, as it resumes talks with world powers in Geneva.
Ayatollah Ali Khamenei said he would not intervene directly in the negotiations, but that he had set “red lines” for Iran’s representatives.
President Barack Obama meanwhile urged US senators not to impose new sanctions on Iran to allow time for diplomacy.
He was unsure if it would be possible to reach an interim agreement soon.
“We don’t know if we’ll be able to close a deal with Iran this week or next week,” he told a Wall Street Journal (WSJ) forum in Washington on Tuesday.
Iran stresses that its nuclear programme is for peaceful purposes only, but world powers suspect it is seeking to develop nuclear weapons.
In a televised speech on Wednesday, Ayatollah Khamenei said Iran’s negotiators had been set clear limits before they travelled to Switzerland for two days of meetings with representatives of the P5+1 – the US, UK, France, China and Russia, plus Germany.
They failed to agree a deal at a previous round of talks earlier this month mainly because of what diplomats said was Iran’s insistence on formal recognition of its “right” to enrich uranium and France’s concerns about the heavy-water reactor being built at Arak.