Uber has been dealt a major setback at Europe’s highest court, with its top legal adviser declaring that the minicab-booking app should abide by strict rules that govern transport providers.

The European Court of Justice’s advocate general said Uber qualifies as a transportation company, rather than a digital service as it had argued.

While the legal opinion is not binding, it is typically followed by judges at the court, meaning Uber may soon have to obey the same strict local laws that govern taxi services in many European countries.

It is the latest setback to Uber, which has fought bitter regulatory battles in many countries and cities, and has lately been engulfed by inner strife and questions about its founder Travis Kalanick.