VIENNA (Reuters) – External factors that have held up the Iran nuclear talks must be resolved in the next few days, the chief British and French envoys said on Friday, warning that otherwise the talks were likely to fall apart. “Fair and comprehensive deal on table – ready for conclusion. External factors must be resolved in next few days or agreement likely to unravel,” Stephanie al-Qaq wrote on Twitter. Her comments were echoed in a separate Tweet by her French counterpart Philippe Errera. (Reporting by John Irish; Editing by Hugh Lawson)