Iran and the United States began a fifth round of negotiations over Tehran's rapidly advancing nuclear program in Rome on Friday, with enrichment emerging as the key issue.U.S. officials up to President Donald Trump insist Iran cannot continue to enrich uranium at all in any deal that could see sanctions lifted on Tehran's struggling economy.

Iranian and US negotiators have resumed talks in Rome to resolve a decades-long dispute over Iran’s nuclear ambitions, Iranian media reports, despite Tehran warning that a new deal might not be possible amid mutually exclusive demands.