Thousands of workers, teachers and civil servants have marched through downtown Casablanca to protest austerity plans put in place by the Moroccan government to control runaway spending.
During the Sunday march, police mounted on motorcycles swooped down and arrested several activists that used the rally as an occasion to denounce the all-powerful monarchy.
Criticism of the elected government in the North African kingdom is tolerated, but not of the hereditary monarchy itself, which the activists claimed was corrupt.
Reform should not be carried out on the back of the poor.
An estimated 8,000 people heeded the call from the three main labour unions to demonstrate in the country's economic capital, as relations between the labour movement and the government worsened.
"We demand the protection of our standard of living," declared one sign carried by protesters. "No to raising the age or retirement," said another, anticipating controversial planned reforms of retirement benefits.
Faced with unrest in 2011 during the Arab uprisings, the previous government raised salaries and benefits, nearly bankrupting the country.
The budget deficit rose to seven percent of GDP in 2012 as subsidy spending rose to $6bn a year.
Under pressure from international lending institutions, it fell to the newly elected Islamist-led government of Prime Minister Abdelilah Benkirane to end subsidies on gasoline and gradually reduce them on diesel.
The unions have opposed these moves, saying it hurts low income groups.
"The government is attacking our standard of living by raising gasoline prices by 25 percent in the last 15 months alone, '' Miloudi Moukharek, head of the Union of Moroccan Workers told the Associated Press news agency ahead of the
demonstration. "Reform should not be carried out on the back of the poor."
On Saturday, Benkirane told supporters the opposition parties were exploiting the union protests for their own ends.