Vienna: UN and Iranian negotiators must make concrete progress in nuclear talks on Monday, the UN atomic agency chief said at the start of high-level talks in Vienna.

Yukiya Amano made the comment to Iranian Deputy Foreign Minister Abbas Araqchi as the two sat down for a meeting over a stalled UN nuclear agency investigation into Iran’s disputed atomic activities.

Araqchi told Amano that Iran had a “new approach” in the negotiations with the agency, which began in early 2012 but have so far failed to show progress. He gave no details.