A massive rally was held in the streets of the Moroccan capital against corruption and official abuses on Sunday.
Protesters filled the Bab el Hed area and marched toward the parliament with support from the Justice and Spirituality Islamist Movement.
The march was organised in support of the recent demonstrations in the impoverished northern Rif and Al Hoceima region, which has been shaken by protests since the death of a fish vendor who was crushed in a garbage compactor while trying to save fish that officials had confiscated.
"We came out to protest about the social reality in Morocco," said Lamia, a school teacher who came from the northern city of Tetouan to the Rabat rally. "We're here in solidarity with Al Hoceima, to demand dignity."
Protester Fatna Afid said: "We are here for dignity, equality, social justice."
While political unrest is rare in the North African kingdom, protests around the northern city of Al Hoceima and the Rif region since October have been the largest since 2011 regional uprisings, which in Morocco led the king to give up some of his powers. Tensions have risen recently due to the arrest of the protest movement's leader Nasser Zefzafi on charges of threatening national security.
Some chanted slogans, including "Your corruption is starting to stink."
The participation of the Justice and Spirituality party is significant. A major player in the 2011 protests, the movement is banned from formal politics, but is the only opposition group able to mobilise on a massive scale.
Police estimated there were more than 10,000 protesters, though Justice and Spirituality said it was much larger. It was the most significant political rally in Rabat since the 2011 unrest and smaller leftist groups and labour unions, as well as some parliamentary opposition parties, also participated.
Some of the anger in the Al Hoceima protests has been directed at "Makhzen", the royal governing establishment, but the unrest has not been aimed at the king. Morocco has a deeply rooted monarchy, the Muslim world's longest-serving dynasty.
The protests threaten the way the Moroccan kingdom presents itself as a model for stability and gradual reform, as well as a safe haven for foreign investment in a region affected by militant violence and political upheaval.