High-stakes talks between Iran and global powers on reining in its nuclear programme will stretch into a third day on Saturday, US officials confirmed. "Over the course of the evening, we continued to make progress as we worked to the narrow the gaps. There is more work to do. The meetings will resume tomorrow morning," a senior State Department official said, after US Secretary of State John Kerry met for some five hours late Friday with his Iran counterpart Mohammed Javad Zarif and EU foreign policy chief Catherine Ashton.