Thousands of people marched in cities across Morocco on Sunday, demanding a new constitution to bring more democracy in the North African kingdom amid the wave of Arab world upheaval.

Demonstrators shouted slogans calling for economic opportunity, educational reform, better health services and help in coping with rising living costs during a march on central Hassan II Avenue in the capital, Rabat.

The day of demonstration was Morocco's entree into the series of protests that have swept up North Africa and the wider Arab world after popular uprisings brought down longtime autocrats in Tunisia and Egypt.

The main target of Sunday's rallies was parliament, where many Moroccans fear their voices are not heard. Still, the protests are likely to pressure King Mohammed VI, who has been seen as a reformer compared to his iron-fisted father, Hassan II, and who still holds absolute authority.

A sea of white banners covered Casablanca's rain-splattered Mohammed V square, where young men in baseball caps and hoods joined young women in Islamic headscarves as well as middle-aged women in black-rimmed glasses and earrings in the diverse crowd.

Plainclothes police mingled among the demonstrators in Rabat, though police were generally discreet. Most marches took place peacefully, officials said.

However, in the city of Marrakech in central Morocco, vandals besieged a McDonald's restaurant and a clothing store in spillover unrest, said a security official on condition of anonymity because he was not authorized to speak publicly on the matter.

And in the northern city of Larache, roaming bands set upon the regional governor's house and set fire to a gasoline station, prompting firefighters to intervene to put out the blaze, the official said.

The self-styled "February 20 movement" _ apparently not for any particular historic reason _ was largely summoned through social media like Facebook.

But the open call to demonstrate also caused confusion, as disparate political and religious groups elbowed their way in and sought to reshape a protest movement to serve their own ends.

One youth-led group initially behind the call to march _ whose name translates as the Freedom and Democracy Now Movement _ canceled its plan to take part on Saturday, saying the movement was hijacked by leftist political parties and Islamists seeking to infuse ideology and faith issues.

The official news agency, MAP, cited a "weak turnout" _ including at 2,000 both in Rabat and the northeastern city of Beni Bouayach, 1,000 in Casablanca, Al Hoceima and Targuist, and 900 in Marrakech.

An Associated Press reporter in Rabat estimated the turnout there at 3,000 to 5,000. Organizers put the turnout outside the parliament building at 20,000.