France's ban on schoolgirls wearing abaya is fanning tension with a father arrested for allegedly issuing death threats to a principal who refused entry to his daughter for wearing the Muslim robe and a United States panel denouncing the French policy.

French police said they were holding a man on Friday, a day after he was arrested for threatening a school principal.

The man was being prosecuted for "issuing threats designed to intimidate a person charged with an official mission," the local prosecutor Dominique Puechmaille told Agence France-Presse.

The man's daughter was stopped at the entrance of her high school on Thursday and asked to remove her abaya. When she refused, she was stopped from entering, police said.

Her father then telephoned the school and spoke first to a guard and then to an educational advisor. He is accused of having issued death threats targeting the school principal in both conversations.

French Education Minister Gabriel Attal called the threats "intolerable and unspeakable".

The principal was now under police protection, he said.

The president of the Auvergne-Rhone-Alpes region, Laurent Wauquiez, added that the school staff had received threats "of death and decapitation."

President Emmanuel Macron's government announced last month it was banning the abaya — a garment worn by Muslim women that covers the body from the neck to the feet — in schools, as it broke the rules on secularism in education.

The ban was quickly challenged before France's State Council, the highest administrative court, by an association arguing it could incite hatred against Muslims and racial profiling.

On Thursday however, the court threw out the complaint.

Wearing the abaya "follows the logic of religious affirmation," the ruling said, adding that the decision was based on French law, which does not allow anyone wearing visible signs of any religious affiliation in schools.

The government ban did not, it said, cause "serious or obviously illegal harm to the respect for personal lives, freedom of religion, the right to education, the well-being of children or the principle of non-discrimination."

Meanwhile, the US Commission on International Religious Freedom said the abaya ban was meant to "intimidate" the Muslim minority.

"While no government should use its authority to impose a specific religion on its population, it is equally condemnable to restrict the peaceful practice of individuals' religious beliefs to promote secularism," CIRF chair Abraham Cooper said.

The United States also has a constitutional separation of church and state but interprets secularism differently, with the government imposing minimal restrictions related to religion.

WITH AFP