Security agents reportedly clashed with peaceful protesters at the Lekki toll gate, Lagos State on Tuesday evening.
The protesters have been demonstrating against police brutality for the past 13 days.
Lekki residents say they heard heavy gunfire around the toll gate.
It was gathered that the lights at the toll gate were switched off before masked men began shooting.
Several persons have been reportedly killed.
Earlier in the day, some Twitter users raised the alarm that closed circuit television (CCTV) at the toll gate had been disconnected.
Videos of continuous gunshots have gone viral on social media.
Amnesty International confirmed the reports in a series of tweets this night.
“Amnesty International has received credible but disturbing evidence of excessive use of force occasioning deaths of protesters at Lekki toll gate in Lagos,” it said.
“While we continue to investigate the killings, Amnesty International wishes to remind the authorities that under international law, security forces may only resort to the use of lethal force when strictly unavoidable to protect against imminent threat of death or serious injury”.
