RABAT (Reuters) - Protesters marking the anniversary of the death of an anti-colonial hero have clashed with police in northern Morocco, in violence which authorities said left 27 officers injured.

Hundreds took to the streets on Sunday night and in the early hours of Monday in the city of Al-Hoceima and other towns of the Rif region, long seen as a hotbed of dissent.

Thousands protested in Al-Hoceima in October against corruption and official abuses after a fishmonger was crushed to death inside a garbage truck as he tried to retrieve fish confiscated by police.

The region was home to Mohammed Ben Abdelkerim El-Khattabi, who fought against Spanish and French occupation in the 1920s and was seen as an opponent of the ruling elite. He died in exile in Egypt on Feb. 6, 1963.

Activists said police used tear gas and rubber bullets against protesters in the latest unrest, injuring some.

Police denied it and said 27 officers were wounded by stones thrown by protesters and were treated in hospital. Authorities made no arrests, they said. Reuters could not independently confirm the accounts.

Activists shared videos on social media showing riot police with batons chasing protesters and throwing stones back at them in Boukidaren, near Al-Hoceima.

“After a group of people organized a sit-in in the town of Boukidaren without meeting the required legal conditions and blocked roads, authorities intervened to disperse the gathering in full respect of the law to reestablish flow of traffic,” a police statement said.

Moroccan authorities heavily police protests, nervous over popular unrest since the 2011 Arab Spring-style protests across the region.