US Secretary of State Hillary Clinton has urged Nigeria to arrest and try those responsible for killing hundreds of people near the city of Jos.
The massacre is seen as revenge for a previous round of killings in January.
Human Rights Watch says the violence has continued because no-one has been held accountable in the past and “it is time to draw a line in the sand”.
Nigerian troops are patrolling the villages which were targeted on Sunday in a bid to prevent further violence.
Acting President Goodluck Jonathan has sacked the country’s national security adviser, Sarki Mukhtar in an apparent response to the killings.
Some have questioned how the attack could have taken place when a military curfew has been in place since January, when at least 200 people died in clashes between rival Christian and Muslim groups.
Christian leaders complained that it took the army two hours to react to a distress call.
The Plateau State Christian Elders Consultative Forum told AFP news agency that by that time, “the attackers had finished their job and left”.