Prominent Black Lives Matters activists and celebrities have written to Nigeria’s president demanding justice over the treatment of people during protests against police brutality.

The group, which includes singer Alicia Keys and campaigner Greta Thunberg, urged President Muhammadu Buhari to free jailed protesters.

They also called for a “transparent investigation” into the alleged killing of protesters by armed forces.

“We cannot stay silent,” they said.

Witnesses say they saw soldiers open fire on protesters in Lagos on 20 October after weeks of protests, which began against the much-hated police unit, the Special Anti-Robbery Squad (Sars), but then morphed into greater calls for better governance.

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“In the midst of a global pandemic, your people sought to bring peace and justice to their land, and they made Africa and its diaspora proud in doing so,” the letter to President Buhari said.

“Yet their peaceful requests were met with state-sanctioned violence and suppression, as your administration meted out unwarranted force against its own unarmed citizens.”

The letter was organised by #BlackLivesMatter movement co-founder Opal Tometi, and timed to coincide with International Human Rights Day.

Other signatories included actors Kerry Washington, Danny Glover and Mark Ruffalo, as well as writers Afua Hirsch, Reni Eddo-Lodge and Naomi Klein.

“As people who have supported the Black Lives Matter movement in the United States and throughout the diaspora, we cannot be silent when similar atrocities take place in African countries,” the letter said.

“We demand respect for the Nigerian people, especially as they engage in their constitutional right to protest grave injustices.”

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As well as demanding the release of all jailed protesters, activists and journalists, the signatories demand that all soldiers and security officials responsible for the alleged shooting at Lekki Toll Gate on 20 October are held to account, and that the ban on peaceful protests is lifted.

Amnesty International says 12 people were killed in the shooting, although the Nigerian army insists its soldiers were firing blank bullets.

A judicial panel has been set up in Lagos to investigate both events at Lekki and the activities of Sars. While it promises neutrality and justice, some protesters say they fear government retribution if they speak out.

Since the protests, a number of activists say they have been targeted by the authorities, the BBC’s Mayeni Jones reports. Some have had their bank accounts frozen by the Nigerian Central Bank and some have been detained without charge, before being eventually released.