Talking thoughout the day continues into night with little let-up before they resume the following morning. Despite all the efforts from both sides there is still no breakthrough to report on the US/EU -Iran nuclear talks.
The major remaining sticking points are the immediate lifting of sanctions, and the level to which Iran is allowed to enrich its own uranium.
President Barack Obama said in his latest TV interview that a big gap remained between the two sides with two weeks left to run until a deal deadline, and he warned the deal might never materialise.
For the last decade Iran has been attempting to deny it has a military nuclear programme, and it insists it is developing nuclear power only.