BERN, Switzerland (AP) — Switzerland will hold a nationwide referendum on whether to ban the construction of minarets where Muslims traditionally issue the call to prayer, officials said.

Swiss nationalists have collected enough signatures to force a vote on the ban, the Interior Ministry said.

Organizers backed by the nationalist Swiss People's Party and the fringe Federal Democratic Union say they are acting to fight the political spread of Islam. They argue that the minaret is a symbol of political and religious claim to power rather than a mere religious sign.

No date has been set for the referendum. If it is approved, the Swiss parliament must pass a law enshrining a construction ban in the constitution.

Minarets are tall spires typically built next to mosques where religious leaders call the faithful to prayer. More than 310,000 among Switzerland's 7.5 million population are Muslims, according to the Federal Statistical Office.

Opponents say such a ban would violate religious freedom.

The U.N. expert on racism, Doudou Diene, has said the campaign is evidence of an "ever-increasing trend" toward anti-Islamic actions in Europe.

President Pascal Couchepin said the government will recommend that voters reject the proposed ban. Several other members of Switzerland's cross-party government have spoken out against the ban.

At least 100,000 signatures are needed to put a popular initiative to a vote in Switzerland.