Amnesty International said Nigerian authorities have refused to launch impartial investigations into the killings.
Amnesty International (AI) has called on the Nigerian government to take urgent steps to end widespread killings in the country.
This is even as the organisation claimed that more than 120 people have been killed since President Bola Tinubu was inaugurated as president on 29 May.
In a statement sent to PREMIUM TIMES, AI's acting director, Isa Sanusi, said attacks by gunmen had claimed 123 people in the two weeks Mr Tinubu had been president.
"It is horrific that attacks by gunmen have claimed at least 123 lives mere weeks after President Bola Tinubu assumed office on 29 May. Rural communities, always bracing themselves for the next bout of violence, are facing deadly attacks by rampaging killers. Protecting lives should be the utmost priority of the new government. The Nigerian authorities must urgently take steps to stop the bloodletting," Mr Sanusi said.
He said authorities in the country had failed to protect people as killings have become a norm.
Mr Sanusi said the killers were being emboldened by the authorities' refusal to launch independent and impartial investigations that could lead to the end of the killings.
"The brazen failure of the authorities to protect the people of Nigeria is gradually becoming the 'norm' in the country. The government said it would enact security measures in response to these attacks, but these promises have not translated into meaningful action that protects the lives of vulnerable communities.
"The Nigerian authorities have also consistently failed to carry out independent, effective, impartial and thorough investigations into these killings -- and this is fueling impunity.
Sign up for free AllAfrica Newsletters
Get the latest in African news delivered straight to your inbox
"The Nigerian authorities are obliged under international human rights law, regional human rights treaties and Nigeria's own constitution to protect the human rights of all people without discrimination -- and that includes the right to life. Those suspected of criminal responsibility for these callous crimes must urgently be brought to justice in fair trials," he said.
Killings, especially in the country's north, have intensified since April.
Terrorists, locally called bandits, have intensified attacks on rural and semi-urban communities, especially in Zamfara, Sokoto, Kaduna and Niger States, leading to the abduction and killing of hundreds of people.
In the North-central part of the country, especially in Benue, Taraba and Plateau States, ethnoreligious clashes have continued to claim lives.
