Representatives from more than 40 European countries are attending a seminar in The Hague to try to ensure that laws on religious freedom are applied across the continent in line with international standards.
The meeting, organised jointly by the Netherlands Government and the Organisation for Security and Co-operation in Europe, aims to co-ordinate the fight against religious extremism and seek guarantees on the right of worship.
Delegates are particularly concerned about the treatment of religious groups which emerged after the collapse of communism in Central and Eastern Europe.
A BBC correspondent in The Hague says the new religions are often regarded as a threat, both to the authorities and to established religions.
Some western European countries have also come in for criticism from human rights groups, who have accused them of fostering discrimination by trying to suppress religious sects.
From the newsroom of the BBC World Service