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 poised to reject a U.S. proposal to end a decades-old nuclear dispute, an Iranian diplomat said on Monday, dismissing it as a "non-starter" that fails to address Tehran's interests or soften Washington's stance on uranium enrichment.