Iran’s supreme leader has questioned whether the Holocaust took place.

In a speech marking the Persian New Year on Friday, Ayatollah Ali Khamenei said: "Expressing opinion about the Holocaust, or casting doubt on it, is one of the greatest sins in the West.

“They prevent this, arrest the doubters, try them while claiming to be a free country. They passionately defend their red lines - how do they expect us to overlook our red lines that are based on our revolutionary and religious beliefs.

“No one dares to speak of the Holocaust. The crux of which is not clear if it is true, or if it were, how it was.”