Mrs Calmy-Rey has been trying to calm the backlash to the Swiss vote
A decision by Swiss voters to ban the construction of minarets poses a risk to Switzerland's security, the country's foreign minister says.
Micheline Calmy-Rey said the Swiss government was "very concerned" about the ban, adopted by voters on Sunday.
"Each limitation on the co-existence of different cultures and religions also endangers our security," she told the European security body, the OSCE.
A top UN official has called the ban "clearly discriminatory".
Navi Pillay, the UN High Commissioner for Human Rights, said the ban was "deeply divisive" and at odds with Switzerland's international legal obligations.
More than 57.5% of Swiss voters and 22 out of 26 cantons - or provinces - voted in favour of the ban on Sunday.
The proposal had been put forward by the Swiss People's Party (SVP), the largest party in parliament, which said minarets were a sign of Islamisation.
Muslim leaders across the world, as well as those of other faiths, criticised the minaret ban as a blow to religious freedom.
But European right-wing groups welcomed the result, calling for other countries to take similar measures.
"Provocation risks triggering other provocation and risks inflaming extremism," Mrs Calmy-Rey said at the OSCE meeting in Athens.
Sunday's referendum has forced the government to declare illegal the building of any new minarets, but Mrs Calmy-Rey said Muslims could still build new mosques and continue to worship in the country.
"Swiss Muslims are well integrated and will continue to attend the 200 mosques in the country," she said.
She said if an appeal against the referendum was lodged at the European Court of Human Rights, it would be up to the court to decide on its legality.