VIENNA - The failure of the 2015 accord between Iran and world powers to restrict Tehran's nuclear programme would be a "great loss", the head of the UN's atomic watchdog said Monday. International Atomic Energy Agency director general Yukiya Amano said Iran was, as of today, "implementing its nuclear-related commitments" under the deal. US President Donald Trump has been a harsh critic of what he calls the agreement's "disastrous flaws". In January, he set a 120-day deadline for US lawmakers and European allies to "fix" the agreement or face a US withdrawal.