The clashes erupted after hundreds of demonstrators took to the streets of Al-Hoceima in the late afternoon despite police roadblocks, activists said.

They said they had planned to hold a major rally but the police "completely locked down" the city, cutting off routes and using force to disperse protesters.

"Residents could not move about freely... the police systematically intervened to stop people from gathering," a journalist in the city told AFP.

Protesters who had come from the neighbouring towns of Imzouren and Tammassin were pushed back by the security forces, he said.

The demonstrators were "brutally repressed by the security forces", the journalist said.

Clashes also broke out in the town of Ajdir between demonstrators and security forces, the journalist said, adding that some people were injured and a dozen arrested.

Al-Hoceima, a key port in the neglected northern Rif region, has been hit by unrest since October.