Muslims girls in Switzerland must not be exempt from mixed swimming lessons, the European Court of Human Rights (ECHR) has said, in a potentially groundbreaking ruling.

The court in Strasbourg threw out an appeal that had been brought by a Muslim couple who said they should be allowed to let their daughters sit out swimming lessons with boys.

It was not a violation of the pupils' human rights to make them take part in mixed swimming lessons, the court ruled, adding that schools has a "special role" in integrating young children, especially those from foreign backgrounds.

"The children's interest in a full education, thus facilitating their successful social integration according to local customs and mores, prevailed over the parents' wish to have their children exempted from mixed swimming lessons," the ECHR said in its ruling.