Iranian officials denied any talks had taken place. One military spokesperson even mocked the claim, saying Americans had been "negotiating with themselves".

The gap is clear. Washington talks about progress; Tehran rejects it outright. But this is not just a disagreement; it reflects deep mistrust, BBC reported. 

That mistrust comes from recent events. 

Over the past year, talks between the two sides have twice raised hopes of easing tensions, with the last round said by their Omani host to have addressed key US concerns about Iran's nuclear programme.