At least 15 people have been killed, including two policemen, since protests against police brutality erupted in Nigeria this month, according to Amnesty International on Monday.
Anger over abuses by Nigeria police's notorious Special Anti-Robbery Squad (SARS) forced the government to scrap the unit, but protests have continued and snowballed into calls for sweeping changes in the West African powerhouse.
One person died in the northern city of Kano on Monday while four others died in Benin City, Abuja and Osogbo over the weekend, Amnesty spokesperson Isa Sanusi told AFP.
Amnesty had reported a death toll of 10 last Thursday, a week after the protests erupted.
In Lagos, home to 20 million people, thousands of people took to the streets again on Monday bringing the economic hub to a standstill.
In the capital Abuja, tensions were high after protestors said they were attacked by suspected hired thugs on Sunday.
"The Nigerian army and police are everywhere, no doubt to stop the peaceful protest," 24-year-old demonstrator Anita Izato told AFP.
Meanwhile, police said one of their facilities was attacked on Monday by "persons posing as #EndSARS protestors" in Benin, Edo state.
"The extent of damage cannot be ascertained at the moment but report indicates that the protesters carted away arms and ammunition from the armoury and freed the suspects in custody before setting some of the facilities ablaze," the Nigerian police said.
A new SWAT force to replace SARS was scheduled to start its training on Monday.
The unit "will operate within very high professional and ethical standards, rule of law and dictates of best international policing practices," a police statement said on Sunday, adding that it would receive training from the International Committee of the Red Cross.