The top UN rights official said on Tuesday Switzerland's ban on building minarets was "deeply divisive" and at odds with its international legal obligations.
Navi Pillay, UN high commissioner for Human Rights, said in a statement that prohibiting an architectural structure linked to Islam or any religion was "clearly discriminatory".
Swiss voters adopted the ban in a referendum on Sunday, defying the government and parliament which had rejected the right-wing initiative as violating the Swiss constitution, freedom of religion and a cherished tradition of tolerance.
Pillay said the ban was "discriminatory, deeply divisive and a thoroughly unfortunate step for Switzerland to take, and risks putting the country on a collision course with its international human rights obligations".
A UN human rights body, composed of independent experts, said last month the ban would bring Switzerland into "non-compliance" with the International Covenant on Civil and Political Rights, which it has ratified.
Pillay's spokesman, Rupert Colville, was asked at a news briefing whether this meant that Switzerland was violating the pact. "It's not quite the same as saying it's a violation, but it is a very short step short of saying that," he said.
Pillay's office might be prepared to submit an opinion if critics of the ban were to challenge it in a court, he said.
The Council of Europe said on Monday the ban raised concern over whether fundamental rights, protected by international treaties, should be the subject of popular votes.
