Hasaan Rowhani stirs up a hornet's nest by acknowledging the Holocaust

As he conducts a high-profile goodwill visit to New York this week, Iranian President Hasaan Rowhani says he is bringing a simple message of peace and friendship.

But on Wednesday he set off a political storm in New York and in Iran with an acknowledgment and condemnation of the Holocaust that landed him in precisely the kind of tangled dispute he had hoped to avoid.

Rowhani, in an interview with CNN, described the Holocaust as a "crime the Nazis committed towards the Jews" and called it "reprehensible and condemnable".

It was a groundbreaking statement, given that his predecessor, Mahmoud Ahmadinejad, denied the systematic extermination of Jews during the second world war. Rowhani largely repeated his comments in a later meeting with news media executives.

But a semi-official Iranian news agency accused CNN of fabricating portions of Rowhani's interview, saying he had not used the word Holocaust or characterised the Nazi mass murder as "reprehensible". Rowhani spoke in Persian; officials at CNN said they used an interpreter provided by the Iranian government for the interview, which was conducted by Christiane Amanpour.

The dispute over his comments reflects the extreme delicacy of the Holocaust as an issue in Iranian-American relations. More broadly, it speaks to the political tightrope Rowhani is walking, trying to negotiate a nuclear deal with the United States that will ease sanctions to please everyday Iranians, without provoking a backlash by hardliners.