The attacks and deadly retaliation are threatening to eclipse Boko Haram as the top security issue leading into next year's election, analysts have warned.
Hundreds of people have been killed in Nigeria's Kaduna state since 2016 as a result of ethnic violence between herdsmen and farmers.
The herdsmen-farmer conflict killed more people than the Boko Haram insurgency in 2016, according to a report.
The president said it would be "very difficult" for Biafra to break away from Nigeria.
Competition for resources and religious affiliation merge in a deadly battle in a country wracked with security threats.
At least five people were killed in Nigeria's Enugu state in the latest clashes between herdsmen and farmers.
Hundreds have died in conflict between herdsmen and farmers in 2016.
Ongoing clashes between Fulani herdsmen and farmers have killed hundreds in 2016.
Fulani herdsmen killed 1,200 people in 2014 and are depriving Nigeria of billions of dollars in revenue.