Diplomats from Iran and the three European parties remaining in a moribund 2015 nuclear deal met in Istanbul on Friday, Iranian and British officials said, their first round of talks since the U.S. began nuclear talks with Tehran in April.

Iran received and is reviewing a proposal for a fifth round of nuclear talks with the United States, Deputy Foreign Minister Kazem Gharibabadi said on Tuesday, according to state media. U.S. President Donald Trump said last week that a new nuclear deal with Tehran was getting very close as the latter was provided with a proposal,

"We don't think it will lead to any outcome," the supreme leader warns, saying the US is making "outrageous" demands on uranium enrichment.