Critics of local French bans on full-body burqini swimsuits have filed legal challenges, forcing the country's highest administrative authority to investigate Thursday whether such bans are actually legal, as photos and video surface showing police forcing Muslim women to disrobe.

Images of uniformed police appearing to require a woman to take off her tunic, and media accounts of similar incidents, have elicited shock and anger online this week.

Some fear that burqini bans in several French towns are worsening religious tensions. The bans, based on a strict application of secularism policies, have exposed division within the government.

Prime Minister Manuel Valls told BFM television Thursday that burqinis represent "the enslavement of women" and reiterated his support for mayors who have banned them.

But Education Minister Najat Vallaud-Belkacem, a feminist with North African roots, said that while she doesn't like the burqini swimsuit, bans of the garment are politically driven and unleashing racist sentiment.

"My dream of society is a society where women are free and proud of their bodies," she said on Europe-1 radio. But with tensions in France high after a series of deadly Islamic extremist attacks, she said, "We shouldn't add oil to the fire" by banning burqinis.

Critics of the local decrees have said the orders are too vague, prompting local police officials to fine even women wearing the traditional Islamic headscarf and the hijab, but not burqinis.

The prime minister, while stressing his opposition to the burqini, urged police to implement the bans fairly and respectfully.

Two human rights groups, arguing the bans are discriminatory, have appealed to the Council of State to overturn the measures.

The council held a hearing Thursday and was expected to issue a ruling on Friday. The ruling specifically concerns a ban in the Riviera town of Villeneuve-Loubet, but the decision will be binding and set a legal precedent on the increasingly heated question of whether cities can tell Muslim women what to wear on the beach.

The Human Rights League and the Collective Against Islamophobia in France say the mayor's decree violates basic freedoms of dress, religious expression and movement.

The Villeneuve-Loubet order bars from local beaches any people whose garments don't respect the principles of secularism, health and safety rules and good moral standards. Like other local decrees, the Villeneuve-Loubet ban doesn't explicitly mention the word "burqini."

The conservative mayor in Villeneuve-Loubet, Lionnel Luca, has said he wanted to foresee any disruption to the public order in a region badly hurt by the deadly Bastille Day truck attack in nearby Nice last month. The two towns are only 9 miles apart.

On Monday, a lower court in Nice ruled that the Villeneuve-Loubet ban was "necessary, appropriate and proportionate." The administrative court added that wearing "conspicuous" religious clothing on the beaches may be seen as a "provocation" by some people and increase local tensions.

The Nice court also said that burqinis can be viewed as an "expression of an erasing" of women and of "a lowering of their place which is not consistent with their status in a democratic society."

Religious clothing is particularly sensitive in France, where an unusually large part of the population has no religious affiliation, and where the first provision in the constitution says France is a "secular Republic."

The Associated Press contributed to this report.