Former US Secretary of State Schultz: Iran 'a tough customer'
21 November 2013 Last updated at 05:01 GMT
The Iranians are good at "smiling, encouraging you on and then cutting your throat" former US Secretary of State George P Shultz has told the BBC.
His comments came as negotiations between world powers and Iran on the future of Tehran's nuclear programme continued in Geneva.
Mr Schultz was himself involved in top level talks as part of the Reagan administration in the 1980s and suggested Iran was "a tough customer" to deal with.
In an interview with the BBC's Sharanjit Leyl, Mr Schultz also gave his view on North Korea and how the crisis in Syria might be resolved.