The talks follow a massive military build-up by the United States in the region not seen in decades, and with President Donald Trump repeatedly threatening strikes should talks fail.

"Our Supreme Leader has already stated that we will not have nuclear weapons at all," Pezeshkian said, in a reference to Ayatollah Ali Khamenei.

"Even if I wanted to move in that direction, I could not -- from a doctrinal standpoint, I would not be permitted."

"If they (the US) strike us, a hundred more like us will rise and run the country. If we stand together and join hands, no power will be able to bring us to a standstill," said Pezeshkian.