A Swiss ban on minarets could violate fundamental liberties, Europe's top human-rights watchdog said Monday in an indication that the heavily criticized vote could be overturned.

The Council of Europe said banning "new minarets in Switzerland raises concerns as to whether fundamental rights of individuals, protected by international treaties, should be subject to popular votes."

The statement by the 47-nation council's secretary-general, Thorbjorn Jagland, suggests a case may be made to seek a ruling by the European Court of Human Rights condemning Switzerland for violating freedom of expression, freedom of religion and prohibition of discrimination.

Swiss Justice Minister Eveline Widmer-Schlumpf said the ban would come into force immediately, but also indicated that the court could strike down the Sunday vote, which incurred swift condemnation at home and abroad for banning the towers used to put out the Islamic call to prayer.

"The ban contradicts the European Convention on Human Rights," Zurich daily Blick cited Widmer-Schlumpf as saying, referring to the 1950 treaty laying out basic rights that the court in Strasbourg, France, was created to ensure member states abide by.

The referendum backed by nationalist parties was approved by 57.5 percent of the population Sunday, forcing the government to declare illegal the building of any new minarets in Switzerland. It doesn't affect the country's four existing minarets.

France's Foreign Minister Bernard Kouchner said he was "a bit scandalized" by the vote, which amounts to "oppressing a religion."

"I hope that the Swiss will go back on this decision rather quickly," Kouchner said on France's RTL radio. "It is an expression of intolerance, and I detest intolerance."

The U.N.'s special investigator on religious freedom, Asma Jahangir, said the ban on new minarets constitutes "a clear discrimination against members of the Muslim community in Switzerland."

Ekmeleddin Ihsanoglu, the secretary general of the Organization of the Islamic Conference, called the ban an "example of growing anti-Islamic incitement in Europe by the extremist, anti-immigrant, xenophobic, racist, scare-mongering ultra-right politicians who reign over common sense, wisdom and universal values."

Wealthy Arab tourists might think twice now about spending their money in Geneva and other Swiss cities popular with visitors from the Gulf, and the neutral country's efforts to mediate in the Israeli-Palestinian conflict could also suffer, said Daniel Warner, a Swiss-American political scientist at the Graduate Institute in Geneva.