Senegal has blocked social media and messaging systems following the sentence of opposition leader Ousmane Sonko.
On Thursday, at least nine people died when Sonko supporters clashed with police in numerous locations.
Sonko was not in court when he was sentenced to two years for immoral behaviour but acquitted of rape accusations.
According to the justice minister, he might be detained at any time, and police have surrounded his house in the capital.
His supporters are concerned that the conviction would preclude the 48-year-old lawmaker from running in next year's presidential election.
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Several neighbourhoods of the capital witnessed skirmishes, with some of the worst being on the university campus in the city centre when police shot tear gas while vehicles burnt and black smoke billowed over the region.
Many establishments were shuttered, and some remained closed on Friday.
There was also unrest at Ziguinchor, Sonko's hometown in the south.
Sonko is immensely popular among unemployed youth and has become prominent in politics in recent years.
He was elected to parliament and became mayor of Ziguinchor after being fired as a tax inspector in 2016.
The administration has denied charges that the opposition leader's case and others he has faced were politically motivated.
In 2021, he was charged with sexually abusing and threatening a massage therapist at a beauty parlour, which he disputed.
The idea that President Macky Sall intends to continue in office for an unlawful third term adds to the political tension, notwithstanding his denials.