Trump administration says it needs more time to plan return of man who was mistakenly deported to an El Salvador prison.
Military head Oligui Nguema is the strongest candidate, but his ties to the old government have led to criticism.
The 15 Muslim families in Nanda Nagar fled after they were attacked by neighbours. Ahamad Hasan decided to return.
Iran's Foreign Ministry says high-level talks were conducted in 'constructive atmosphere and based on mutual respect'.