Christians in central Nigeria have fallen victim to "horrific, opportunistic" attacks by armed radicals during the coronavirus lockdown.
Open Doors said that at least 32 people, including a pregnant woman, had been killed in raids on villages in two states north of capital Abuja.
Three people were killed and several others seriously injured when suspected Fulani militants launched a night-time raid on the community of Ancha in Plateau State on April 1.
Many were left without anywhere to stay after the militants set fire to at least 17 homes.
On March 30, at least 10 Christians were killed when Islamist militants went on the rampage in villages in Plateau State and Kaduna state.
The attacks occurred at a time when many people were staying at home due to the coronavirus pandemic.
"These are horrific, opportunistic attacks on people who are defenceless in their homes during lockdown," said Jo Newhouse, regional spokesperson Open Doors.
"The Government needs to ensure the safety of all Nigerians during the Covid-19 lockdowns and to address the impunity with which attacks like these continue.
"If people are going to stay in their homes during the COVID-19 pandemic, they need to feel safe from terrible attacks like this."
Sunay Abdul, a community leader in Ancha, told the organisation that the attackers "burnt houses at random", as well as cars.
"There were so many [attackers] that nobody could resist them," he said.
Another community leader, Nuhu Nkali, expressed anger towards security agents, saying that the bloodshed "could have been prevented".
"We don't know what we have done to warrant this wickedness against our people," said Nkali.
"The community made efforts to alert security agents, but nothing was done to prevent it."