A number of people taking part in a protest against police brutality have reportedly been shot dead or injured in Nigeria’s biggest city, Lagos.
An eye witness said he had counted about 20 bodies and at least 50 injured after soldiers opened fire. Amnesty International said it had obtained credible reports of deaths.
The authorities have promised an investigation into the shooting.
An indefinite 24-hour curfew has been imposed on Lagos and other regions.
Protests over a now-disbanded police unit, the Special Anti-Robbery Squad (Sars), have been continuing for two weeks.
Nigerian footballer Odion Jude Ighalo, who plays for Manchester United, accused the Nigerian government of killing its own citizens. “I’m ashamed of this government,” he said in a video posted on Twitter.
Eyewitnesses spoke of uniformed men opening fire in the wealthy Lekki suburb of Lagos on Tuesday evening.
Armed soldiers were seen barricading the protest site moments before the shooting, BBC Nigeria correspondent Nayeni Jones reports.
Social media footage streamed live from the scene shows protesters tending to the wounded.
An unnamed eyewitness told BBC News: “At exactly 6.45pm [local time] the soldiers pulled up… and they started firing directly at we, the peaceful protesters.
“They were firing and they were advancing straight at us. It was chaos. Somebody got hit straight beside me and he died on the spot.
“It was pandemonium and they kept on shooting and shooting at us. It lasted for about an hour and a half and the soldiers were actually taking up the dead bodies.”
He said the soldiers had built a barricade and ambulances could not reach the protest area.
Amnesty International spokesman Isa Sanusi later said: “People were killed at the tollgate by security forces… we are working on verifying how many.”
Gboyega Akosile, a spokesman for the Lagos state governor, tweeted: “There have been reports of shooting at the Lekki Toll Plaza, following the 24-hour curfew imposed on Lagos State to stop criminals who hid under the #EndSARS protests to unleash mayhem on innocent citizens.”
He said the state authorities had ordered an “investigation into the incident”.
Protests began nearly two weeks ago with calls for the Sars, which had been accused of illegal detentions, assaults and shootings, to be disbanded.
President Buhari dissolved the unit on 11 October.
But the demonstrators called for more changes in the security forces as well as reforms to the way the country is run.
Lagos state Governor Babajide Sanwo-Olu has said that criminals have hijacked the protests