Tens of thousands of people demonstrated around Morocco both for and against a proposed new constitution on Sunday, just a week before it is to be voted on in a referendum.
In Morocco's largest city, Casablanca, government supporters first blocked then attacked with rocks a march by thousands of activists, wounding many.
King Mohammed VI announced a new constitution June 17 following unprecedented nationwide protests for greater freedoms in the preceding months.
He said the new document would turn the country into a constitutional monarchy and would widen the space for democracy.
The draft proposal gives the prime minister and the parliament greater powers, more independence to the judiciary and guarantees human rights, gender equality and an equal role to the Berber language.
Pro-reform activists, however, say that the draft, which was drawn up by a commission chosen by the king, leaves the monarch's absolute powers intact. Mohammed VI remains the head of the army and country's pre-eminent religious figure.
Backed by the official political parties, the government has launched an energetic media campaign in support of the new constitution ahead of the July 1 referendum.
Supporters of the government are now organizing demonstrations to rival those of the February 20 pro-democracy movement, often resulting in scuffles between the two sides.
In Casablanca, tens of thousands of pro-government demonstrators from all over the country waved the national flag, carried portraits of the king and shouted slogans in support of the new constitution.
On the other end of town, some 5,000 activists from the February 20 pro-democracy movement marched against the constitution in the lower income Hay Mohammedi neighborhood.
Their march, however, was blocked by young government supporters, mostly shirtless in the heat and carrying pictures of the king.
When they were cleared away by riot police, these young men circled through the alleys of the slum and attacked the opposition rally, hurling rocks and provoking a stone-throwing riot.
At least one police commander was seen getting hit by a stone before calm was restored and the march continued.
In downtown Rabat, the capital, a march of at least 2,000 protesting against the constitution was blocked by police and a few hundred government supporters.
The two groups, separated by riot police, chanted rival slogans. Activists reported brief scuffles and some injuries.
"We have decided since they won't let us march we will hold an open-ended sit in until they let us move," said Omar Radi, an activist with the February 20 movement.
Videos posted on the Feb. 20 website also showed demonstrations in the cities of Tangiers, Marrakech and Tetouan.
The official news agency reported that demonstrations supporting the constitution had taken place everywhere around the country Sunday, involving half a million people.
Like other official media organs, the agency did not mention the demonstrations against the constitutional project.
Paul Schemm reported from Paris.