Khatibzadeh wrote on his Twitter page on Thursday: "Fiery tweets (which contradict the tone you actually use) may make good headlines."
A spokesman for the diplomatic corps stressed: But the slogan can never be the answer to the legal rulings issued by the courts.
He referred to the remarks of Foreign Minister Hossein Amir-Abdollahian and continued:
As Foreign Minister Dr. Amir-Abdollahian made it clear, Britain needs to change its approach, and that change has long been delayed.
The British Foreign Secretary claimed on Thursday night that London had put pressure on Tehran over the case of Nazanin Zaghari.
In a Twitter message, Truss referred to his meeting with Amir-Abdollahian yesterday and wrote: "Zaghari is going through a difficult experience, we are trying to bring him home and to his family."