Hundreds of thousands of Moroccans are demonstrating to protest the U.N. chief's remarks about the contested Western Sahara territory.

Morocco considers the vast mineral-rich region as its "southern provinces" and took offense when U.N. chief Ban Ki-moon used the word "occupation" after a visit this month to refugee camps for the region's native Sahraouis in southern Algeria.

Protesters on Sunday filled the streets of Rabat after leading Moroccan political parties, unions and non-governmental groups called for a national demonstration. Authorities claimed there were up to 3 million.

The U.N. has been trying for years to hold a referendum on independence for the territory, which was annexed by Morocco when Spain withdrew in 1975. Morocco proposes increased autonomy instead.

Ban also called for renewed peace efforts during his trip.