Iran's President Ahmed Raisi cancelled a long-planned interview with CNN's veteran journalist Christiane Amanpour at the United Nations General Assembly on Wednesday after she declined his demand that she cover her head with a scarf during the interview.

The cancellation of the scheduled interview comes at a time when Iran is seeing a nationwide protest over the death of a 22-year-old woman Mahsa Amini, who reportedly died of a 'heart attack' hours after morality police arrested her for violating the country's mandatory rule for women to cover their head in public.

Raisi, a hard-liner who was in New York to attend the UN General Assembly session, had a scheduled interview with Amanpour, CNN's chief international anchor, the network reported.

The Iranian president cancelled the interview after she declined a last-minute demand to wear a headscarf, CNN said.

Amanpour in a series of tweets said that Raisi's aide made it clear that an interview would not happen if she did not wear a headscarf, as it was the months of Muharram and Safar and hence is "a matter of respect".

I very politely declined on behalf of myself and CNN, and female journalists everywhere because it is not a requirement", Amanpour was quoted as saying by CNN.

Amanpour, 64, who grew up in Tehran said she often wears a head scarf while reporting in Iran to comply with the country's laws but she could not cover her head to interview an Iranian official outside a country where there is no such compulsion.

Here in New York, or anywhere else outside of Iran, I have never been asked by any Iranian president and I have interviewed every single one of them since 1995 either inside or outside of Iran, never been asked to wear a head scarf, she said on CNN's New Day programme on Thursday.

The death of Mahsa while in police custody has since then sparked outrage and has seen women coming on the streets to burn their 'hijab' (headscarf). Some have also posted videos on social media of cutting their hair.

The protests, which are in their seventh day, have caused the death of at least 26 people, as per Iranian's state TV.