Moroccans are voting in a referendum on a revised constitution seeking to curb King Mohammed VI's near absolute powers in the north African nation.

Mohammed announced the referendum last month in what is widely seen as a move to ward off "Arab Spring" street protests sweeping the region.

Polls opened at 8am (0700 GMT) and were to close at 7pm with preliminary results expected on Friday or early on Saturday.

About 13 million of the country's 32 million people were registered to vote.