Police in Chad fired tear gas and made several arrests as hundreds protested against President Idriss Deby's nomination on Saturday to run for a sixth term in April after 30 years in power.
In the capital N'Djamena on Saturday, hundreds of protesters set tyres on fire and chanted "No to a sixth term!" and "Leave, Deby!", according to witnesses.
Police fired tear gas and arrested several people, including Mahamat Nour Ibedou, a prominent human rights activist.
Protests were also held in the cities of Moundou, Doba, Sarh and Abeche.
The protests followed the announcement that the ruling Patriotic Salvation Movement (MPS) party had backed President Idriss Deby's bid for a sixth term in office.
Deby, 68, who came to power in a 1990 rebellion, pushed through a new constitution in 2018 that reinstated term limits but would let him stay in power until 2033.
His opponents accuse him of crippling Chad's institutions in a bid to hold on to power.
Human rights groups regularly raise objections to banned opposition demonstrations, arbitrary arrests and severed access to social networks.
Build up of frustration
Chadian Rap artist Ray’s Kim, who was at the rally, said it was about the need to change the whole system.
"Chadian people today, have every reason to be angry and show our frustration," he said. "Imagine a government which doesn't respect you and doesn't consider you. So if this kind of government exists, we must push it aside and replace it with another."
Ahead of the April election, 12 opposition parties last week said they would field a joint single candidate. They also signed a deal creating an electoral coalition called Alliance Victoire (Victory Alliance).
Signatories include two prominent opposition figures – Saleh Kebzabo, the runner-up in the 2016 election with about 13 percent of the vote, and Mahamat Ahmat Alabo.
Deby has faced strikes and protests in recent years over economic woes caused by low oil prices and armed rebellions in the desert north, where former colonial power France has intervened in support of the government.
During his rule, Deby has been accused of appointing relatives and cronies to key positions and failing to address the poverty that afflicts many of Chad's 13 million people despite oil wealth.
The country ranks 187th out of 189 in the UN's Human Development Index.
Chad is an ally of Western nations in the fight against Islamist militants in West and Central Africa and one of the largest contributors to the UN peacekeeping mission in Mali.