Nigerian President Muhammadu Buhari has called for communities to unite to ease tensions after violence in a flashpoint central city killed dozens of people.
Jos, in Plateau State, has in the past suffered from clashes between Muslim and Christian communities, although local officials say recent attacks are the work of criminals rather than religious violence.
At least 23 Muslim travellers were killed earlier this month when their bus convoy was attacked outside Jos. Police had blamed a suspected Christian militia.
Just over a week later, gunmen descended on a predominantly Christian village on the outskirts of the city, shooting dead at least 18 people and setting homes on fire.
"The Presidency wishes to assure all citizens that as a government, the administration is on top of events and is moving ahead with force to crush the perpetrators," a statement from Buhari's office said late on Sunday.
"But to achieve success, our communities must unite against these horrific attacks. Retributive violence is not the answer."
Plateau State officials put Jos city and its surroundings under a 24-hour curfew as a security measure. That was relaxed to a 6pm to 6am curfew on Monday, an AFP reporter in the city said.
Both Fulani Muslim leaders and Christian Irigwe representatives denied their communities were involved in tit-for-tat attacks.
Buhari, a former soldier first elected in 2015, is under fire from opponents over a surge in insecurity in Africa's most populous nation.
Nigerian troops are battling a 12-year jihadist insurgency in the northeast that has killed more than 40,000 and forced over 2 million more from their homes.
Parts of northwest and central Nigeria have long struggled with clashes between nomadic herders and local farmers over water and land.
But violence in those regions has escalated with increasing attacks from heavily armed criminal gangs who raid and ransack villages, loot cattle and kidnap for ransom.
This year, the armed gangs known locally as bandits, have targeted schools and colleges for mass abductions for ransom.
More than a 1,000 children have been snatched in a string of attacks since December, according to UNICEF, though most have been freed after negotiations.
Last week, gunmen released more than 100 more pupils held after three separate attacks, some having been in captivity in forest hideouts since May.