Swiss voters are casting ballots Sunday in a referendum on amending the country's constitution to ban the construction of Islamic minarets.
The nationalist Swiss People's Party and a fringe party, the Federal Democratic Union Party, are behind the controversial proposal.
Many nationalists say they have no problem with the construction of mosques in Switzerland. But they say they object to minarets -- tall spires that many mosques have -- from which religious leaders call the faithful to prayer.
Supporters of the ban say minarets are often paid for by extremists and used as a political symbol, which they say violates the Swiss constitution. And, they argue that minarets are not obligatory in Islam.
Other Swiss - Muslim and non-Muslim - see the referendum as a threat to religious freedom.
Switzerland has an estimated 400,000 Muslims, about five percent of the population. There are four minarets in the small Alpine country.
The growth of Muslim communities across western Europe has raised concerns among non-Muslims about Islamic influence on local cultures. Protests against building new mosques have taken place in many countries.
France has banned all religious symbols in public schools, including head coverings for Muslim girls.