Iran talks in endgame inching close to nuclear deal

After months of intense negotiations, global powers and Iran launched into a key weekend of talks today amid signs they may be within sight of a historic nuclear deal to end a 13-year standoff.

While all sides remained cautious, Iranian Foreign Minister Mohammad Javad Zarif said the world had "never been closer" to reaching an unprecedented accord with his country aimed at blocking Iran's pathways to developing nuclear arms.

In signs of a possible breakthrough on one of the thorniest issues still blocking a deal, the IAEA announced today that it may be able to complete a probe into whether Iran has ever sought nuclear weapons by the end of the year.

In a rare move, Zarif also offered the promise of greater cooperation to tackle other global problems, such as the rise of the Islamic State group, should the deal be sealed.

Global powers are trying to draw the curtain on almost two years of roller-coaster negotiations, which gathered fresh impetus after President Hassan Rouhani took power in late 2013.

The aim is to finalise a deal which would put a nuclear bomb beyond Iran's reach, in return for lifting a web of biting international sanctions slapped on the Islamic republic, some of which date back to 1995.

Speaking in English from the balcony of the Viennese hotel hosting the talks, Zarif said in a message posted on YouTube that at "this 11th hour, despite some differences that remain, we have never been closer to a lasting outcome".

"Getting to yes requires the courage to compromise, the self-confidence to be flexible, the maturity to be reasonable," he said.

But he added that Iran was ready to strike "a balanced and good deal" which could "open new horizons to address important common challenges".

"Our common threat today is the growing menace of violent extremism and outright barbarism," he said in a clear reference to the Islamic State (IS) jihadist group that has overrun parts of Syria and Iraq.

Meanwhile, IAEA chief Yukiya Amano told reporters as he re-joined the nuclear negotiations that progress had been made as the International Atomic Energy Agency (IAEA) seeks to ensure that any deal is "technically sound."

"With the cooperation from Iran I think we can issue a report by the end of the year on the ... Clarification of the issues related to possible military dimensions," Amano told reporters after returning from talks in Tehran earlier this week.