SENEGAL police are using armed civilians to violently quell protests that kicked off following the arrest of opposition leader Ousmane Sonko, demonstrators and human rights groups have warned.

At least 23 people were killed earlier this month during the country’s deadliest clashes between police and protesters in decades, according to Amnesty International.

Several people were reported to have been shot with live ammunition by men wearing civilian clothes who appeared to be fighting alongside the police, according to protesters and rights groups.

Protester Cheikh, who was inches away when a bullet struck his friend Khadim Ba, said: “We thought tear gas and grenades would be used against us.

“We had no idea they would shoot.”

The 21-year-old was killed on June 1 – the same day Mr Sonko was convicted of “corrupting youth” and given a two-year prison sentence.

Mr Sonko’s supporters maintain the conviction was the latest episode in a long-running effort by President Macky Sall to derail the opposition leader’s candidacy in the 2024 presidential election.

Protesters refer to gunmen for hire who are deployed to shut down protests as “nervis,” which is French for thugs.

Cheikh, whose last name is not revealed for his safety, said that he and other friends recognised Mr Ba’s alleged killer as someone close to a local well-known wrestler.

He recalled seeing the man shooting people with a pistol while standing in front of riot police.

While individual accounts are difficult to verify, video images on social media show non-uniformed men holding guns and standing alongside the police during the series of demonstrations.

Men believed to be part of the recruited “nervis” also were spotted outside the ruling party’s headquarters in Dakar, Amnesty International researcher Ousmane Diallo said.

Senegal’s government denies armed civilians collaborated with police.