Iran's Foreign Minister has underlined that no direct talks have been held with the US.

Attending a meeting with the representatives of the Parliament's Commission of National Security and Foreign Policy, Amir-Abdollahian presented a report about the process of the Vienna talks on lifting sanctions, JCPOA-related commitments, ensuring guarantees, and verification.
  
The top diplomat stressed that no direct talks had already been held between Iran and the US, adding that the two sides were made their technical comments through informal written notes or non-paper, mediated by the EU Coordinator.
The eighth round of Vienna talks for lifting sanctions is underway with the presence of Iranian delegations and the P4+1 group (Germany, France, Britain, Russia, and China) in Vienna, the capital of Austria.
The US delegation is also in Vienna negotiating with the P4+1 group. 
Meanwhile, the US is seeking a kind of direct negotiations with Iran, through sending various messages.