A number of people taking part in a protest against police brutality have reportedly been shot dead or wounded in Nigeria's biggest city, Lagos.
Witnesses quoted by local media said up to 12 people had been killed and others wounded after soldiers opened fire. Amnesty International said it had obtained credible reports of deaths.
The army denies the reports. Officials have promised an investigation.
An indefinite 24-hour curfew has been imposed on Lagos and other regions.
The BBC's Nduka Orjinmo in Nigeria said a small group of protesters were defying the curfew on Wednesday and had gathered at the Lekki toll plaza in Lagos where the shooting took place.
Protests over a now-disbanded police unit, the Special Anti-Robbery Squad (Sars), have been continuing for two weeks. The protesters are using the social media hashtag #EndSars to rally crowds.
Reacting to Tuesday's shootings in the wealthy Lekki suburb, former US Secretary of State Hillary Clinton called on Nigerian President Muhammadu Buhari and the army "to stop killing young #EndSARS protesters".
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.

By d special grace of Allah,everybody DAT has hand in d killings in Lagos yesterday,they I'll use their hand to bury their own children