Muslim leaders from around the world, senior church figures, European politicians and human rights experts have deplored Switzerland's decision to ban the building of minarets.

The polarising verdict in a Swiss referendum held yesterday raised fundamental questions about discrimination and freedom of religion, with the Swiss government itself doubtful over whether the popular vote could be translated into national law, as required by the country's system of direct democracy.

"Scandalous," said the French foreign minister, Bernard Kouchner, while Babacar Ba, a senior official of the Organisation of the Islamic Conference, warned of an "upsurge in Islamophobia" in Europe.

But far right leaders in Europe applauded the Swiss vote and called for parallel prohibitions in other countries.

"The flag of a courageous Switzerland which wants to remain Christian is flying over a near-Islamised Europe," said Mario Borghezio, an MEP from Italy's anti-immigrant Northern League.

In the Netherlands, the anti-Muslim Freedom party of Geert Wilders, which is steadily growing in popularity, called for a similar vote for the Dutch. "It's the first time that people in Europe have stood up to a form of Islamisation," it declared.

Despite Swiss fears of a violent backlash in the Islamic world and business fears of an adverse impact on Arab spending in Geneva and Zurich, as well as exports to the Middle East, Muslim leaders reacted mostly with sorrow. "The main thing is to keep calm and to realise how much work still needs to be done to defend basic freedoms," said Ba, the OIC ambassador in Geneva."We must do this by taking a constructive part in the debate on all issues which cause fear and concern, and to try to bring people together in order to confront extremism."

The surprisingly high vote of 57% for the minaret ban put the Swiss government and establishment on the defensive, engaged in damage limitation. In Brussels, the Swiss justice minister, Eveline Widmer-Schlumpf, who opposed a ban, argued that the vote was neither against the Muslim community nor against Islam. She sought to explain the decision to EU interior ministers, some of whom were highly critical.

The Vatican denounced the ban as an infringement of religious freedom.

Roman Catholic bishops in Swizerland issued a statement regretting the ban, accusing the rightwing Swiss People's party, which spearheaded the prohibition campaign, of caricaturing and exaggerating the alleged threat posed by Muslims, and also warned that the ban "will not help Christians oppressed and persecuted in Islamic countries".

Under the rules of Switzerland's direct democracy, which leans heavily on single issue referenda, yesterday's vote compels the government to amend the constitution. The article defining church-state relations will acquire a new sentence stating: "the building of minarets in Switzerland is forbidden".

But the government and parliament knows that this will breach the European convention on human rights and the UN charter proscribing discrimination on religious grounds and entrenching freedom of religion.

The clause would be discriminatory because it singles out one religion, Islam, for restrictive treatment.The backers of the campaign respond that this is irrelevant since minarets have nothing to do with religion, but are a "political symbol". Mosque-building is not being banned and Muslims in Switzerland are free to observe their religion, they argue.

While there are only four minarets in a country that is home to 400,000 Muslims, a dispute over the erection of another minaret in the town of Langenthal is stuck in the courts amid appeals and counter-appeals about building licences.

The case could now end up at the European court of human rights in Strasbourg, taking years to be settled.