A top European Union legal advisor says the bloc's fisheries agreement with Morocco is invalid because it does not respect the rights of people in the disputed Western Sahara region.

In an opinion for the European Court of Justice Wednesday, Advocate General Melchior Wathelet said Western Sahara people have a right to self-determination and possible sovereignty over natural resources there.

He said that EU fishing in waters off Western Sahara "does not respect the right of the people of Western Sahara to self-determination."

Morocco considers the vast, mineral-rich Western Sahara as its "southern provinces" and fiercely defends against anything it considers a threat to its territorial integrity.

While not binding on the ECJ, such legal opinions are usually endorsed by the court in most cases.