The jailing of demonstrators for up to 20 years over unrest in 2016 sparked anger in Morocco on Wednesday, with some warning it could threaten further instability.
At the end of a nine-month trial the figurehead of the Al-Hirak al-Shaabi or "Popular Movement", Nasser Zefzafi, was sentenced to 20 years along with three others for "plotting to undermine the security of the state".
A further 49 people were sentenced late Tuesday to jail terms of one to five years, along with fines, at the Casablanca Court of Appeal.
Social unrest in the northern Rif region began in October 2016 after the death of a fisherman and spiralled into a wave of protests as people demanded jobs and development.
Supporters left the court on Tuesday shouting slogans such as "Long live the Rif", a region where the marginalised Berber ethnic group is the majority.
Followed the sentencing rallies were held overnight in the port city of Al-Hoceima -- the epicentre of the protest movement -- and nearby Imzouren, according to local media.
The Moroccan Association of Human Rights (AMDH) described the judgement as a "mockery of justice", while numerous Moroccan media stressed the severity of the sentences.
Nabila Mounib, leader of the opposition Unified Socialist Party, decried the "disastrous decision by the state (which) threatens the stability and cohesion of the country."
Similar criticism filled social media, as thousands of users replaced their profile photos with a black image and wrote of the "shame" they felt in the face of such "injustice".
Sentences against paedophiles were more lenient than those meted out to the protesters, some commented.
Some internet users warned of a return to a period of widespread rights abuses under king Hassan II who reigned from the 1960s to the 1990s.
The recent unrest in the Rif region began when fisherman Mouhcine Fikri was crushed to death in a rubbish truck, while he was apparently trying to retrieve swordfish seized by authorities as it was caught out of season.