A senior Iranian official told CNN the new nuclear deal proposal presented to Tehran in recent days is “incoherent and disjointed,” as sources familiar with the progress of the talks said the momentum behind negotiations to secure a new deal appears to be collapsing.

Iran is engaging on multiple diplomatic fronts as it weighs a new US proposal and braces for potential censure by the UN’s nuclear watchdog.

Iranian and U.S. delegations wrapped up a fifth round of talks in Rome on Friday and signs of some limited progress emerged in the negotiations aimed at resolving a decades-long dispute over Tehran's nuclear ambitions.