Amnesty International has accused Nigerian security forces of killing at least 21 protesters during a week of rallies against economic hardship, the national head of the rights group told AFP on Wednesday.
Police have clamped down on protests after thousands of people joined protests against government policies and the high cost of living last week.
AFP correspondents have seen security forces shooting rifles above crowds and firing tear gas to break up demonstrations.
Security forces have denied responsibility for deaths during the protests, which have since dwindled.
Raising an earlier toll of 13, Amnesty's Nigeria director Isa Sanusi said the group had verified seven further killings in the northern city of Kano and one in Azare, in northeastern Bauchi state.
In an interview with AFP, he said this represented a "conservative figure" and that Amnesty was investigating more deaths.
Sanusi said the 21 dead were all protesters killed by security forces. He condemned the use of live ammunition and called for investigations into the conduct of security forces.
"Their duty is to restore order and make sure that protesters are protected," he said.
Police in Kano did not respond to AFP's requests for comment, but have said they are investigating accusations that officers are responsible for deaths in the city.
Africa's most populous country is suffering its worst economic crisis in a generation following reforms brought in last year by President Bola Ahmed Tinubu, including the removal of a fuel subsidy.
On Wednesday Tinubu addressed the nation, again appealing for patience with the reforms, which the government says will improve the economy in the long term.
"Please have faith in our ability to deliver and in our concern for your wellbeing. We will get out of this turbulence," he said.
Dubbed #EndbadGovernanceinNigeria, the protest movement won support with an online campaign that called for the government to reduce fuel prices and tackle the cost of living crisis, among other demands.
The rallies have petered out in many parts of the country, but hundreds of protesters took to the streets in northern states earlier this week.
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