Secretary of Supreme National Security Council (SNSC) Hassan Rowhani tendered his official resignation to President Mohammad Khatami, IRNA reported on Wednesday.
Rowhani in his resignation letter provided a report on his and the SNSC's performance in connection with the country's nuclear dossier, the report added.
As Iran came under increasing Western pressure during 2003 over its nuclear program, Rowhani emerged as the country's chief negotiator. He was often described by Western sources as a "moderate" or "pragmatic conservative".