Companies may bar staff from wearing Islamic headscarves and other visible religious symbols under certain conditions, the European Union's top court ruled on Tuesday, setting off a storm of complaint from rights groups and religious leaders.

In its first ruling on a hot political issue across Europe, the Court of Justice (ECJ) found a Belgian firm which had a rule barring employees who dealt with customers from wearing visible religious and political symbols may not have discriminated against a receptionist dismissed for wearing a headscarf.

The judgment on that and a French case came on the eve of a Dutch election in which Muslim immigration is a key issue and weeks before France votes for a president in a similarly charged campaign. French conservative candidate Francois Fillon hailed the ruling as "an immense relief" that would contribute to "social peace".

But a campaign group backing the women said the ruling could shut many Muslim women out of the workforce. And European rabbis said the Court had added to rising incidences of hate crime to send a message that "faith communities are no longer welcome".

More at Reuters.