RABAT (Reuters) - Tens of thousands of people took to the streets of Morocco’s capital Rabat on Sunday to demonstrate against the jailing of leaders of a protest movement in the predominantly Berber region of Rif.

A woman shouts slogans during a demonstration against the Moroccan court after the jailing of Moroccan activist and leader of "Hirak", Nasser Zefzafi, and a number of other activists, in the Moroccan capital of Rabat, Morocco July 15, 2018. REUTERS/Youssef Boudlal

Carrying pictures of the detained activists and waving Berber blue, green, yellow and red flags, demonstrators chanted “Freedom, dignity and social justice”, “Long live the Rif”, and “The people want immediate release of Rif detainees”.

In June, a court in Casablanca sentenced 39 people, including protest leader Nasser Zefzafi, to terms of up to 20 years in jail in connection with a protest movement that shook Morocco in late 2016 and early 2017.

The protests erupted after a fishmonger was crushed inside a rubbish truck while trying to recover fish confiscated by police in the northern city of Al-Hoceima in October 2016.

Detainees and their families had called for Sunday’s march, which brought together Berber (Amazigh) groups, leftist opposition parties, human rights groups and the banned Islamist movement Al-Adl wal-Ihsan.

Detainees’ relatives, exhausted by a 12-hour bus journey from Al-Hoceima to Rabat, expressed grief and frustration as they marched.

“We will keep up our protests until the release of our sons,” Zefzafi’s mother Zoulikha told Reuters.

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Addressing crowds that activists said numbered at least 30,000, Zefzafi’s father, Ahmed, invoked post-independence grievances and marginalization in the Rif region and denounced what he called a political verdict.

“Rif is uniting Morocco in this march,” he said.

Moroccan authorities estimated that 6,000 to 8,000 of protesters at the march were Al-Adl wal-Ihsan supporters. They did not give an overall estimate of the crowd size.

The Al-Hoceima demonstrations, along with protests in the mining town of Jerada in early 2018, marked the biggest unrest in Morocco since Arab Spring protests in 2011 prompted King Mohammed VI to devolve some of his powers to an elected parliament.

After the Rif protests the king dismissed three ministers and various other officials over a lack of progress in a development plan for the Rif.

Ahmed Dgherni, one of the founders of the Berber (Amazigh) movement, called the march “a popular referendum that united different political trends” to back the cause of freedom.

“The security approach adopted by the state derailed the peaceful protests in the Rif, leading to confrontations and arrests,” he told Reuters.

Senior Al-Adl wal-Ihsan leader Omar Amkasso said the march was “to call for the immediate release of activists and the development of Morocco’s marginalized regions”.

After last month’s verdicts, a lawyer representing the state said the sentences were lenient and that some of the accused had been indicted for serious crimes including attacking law enforcement officers.

Lawyers of Rif activists say they will appeal against the sentences.