Tehran on Saturday strongly condemned a UN report on the Islamic republic's response to mass protests in 2022, denouncing Western countries' "Iranophobia".

The report was built on "baseless claims" and "false and biased information, without a legal basis", foreign affairs ministry spokesman Nasser Kanani said in a statement.

International experts said the repression of mostly peaceful protests beginning in September 2022 and "institutionalised discrimination" towards women and girls have led to "crimes against humanity".

The UN Human Rights Council mandated the experts' investigation -- in which Iranian authorities refused to take part -- following massive protests which shook the Islamic republic after the death in police custody of Mahsa Amini.

A 22-year-old Iranian Kurdish woman, Amini had been arrested by the morality police in Tehran for an alleged breach of the country's strict dress code for women.

"Not only did the expert committee not establish the truth, but it also deliberately distorted the facts," Kanani said.

The report, he said, "was prepared by the Zionist regime (Israel), the United States, and some Western countries", who were "continuing a project of Iranophobia and defamation of Iran".

These countries were "angry at the failure of their interventions during the riots", Kanani said, referring to the protests.

Iranian authorities say the "riots" were fomented by the "enemies" of the Islamic republic, especially the United States.

The spokesman said a special committee charged by Iranian President Ebrahim Raisi with investigating the protests had "recently sent its final report to the president", without giving details on its findings.

The UN experts said "no less than 551" protesters were killed by security forces, who "used unnecessary and disproportionate force".