Nigerian President Muhammadu Buhari arrives to attend the inauguration of Lagos Rail Mass Transit Blue line at Marina station in Lagos on January 24, 2023. AFP
"We now have approximately 40 people that were killed" by the explosion on Wednesday in Rukubi, a village on the border between Nasarawa and Benue states, said Nasarawa's governor Abdullahi Sule.
"The rumour earlier was that the air force carried out the bombing but right now we understand that there was no air force plane that flew (above) the area," Sule told Arise News television late Wednesday.
"Instead it was a drone that flew (above) the area and dropped the bomb," Sule said, without specifying who was operating the aircraft.
An umbrella group representing herders had said the bomb was dropped by a Nigerian military jet.
Nigeria's air force spokesman did not respond to AFP requests for comment.
Herders and farmers in central Nigeria have been clashing over grazing and water rights for decades, but the violence has worsened in recent years after some herders joined criminal gangs that raid villages.
The conflict has also taken on an ethnic and religious dimension, with most herders being Muslims while farmers are largely Christians.
Last Thursday, nine people were killed when suspected herders opened fire outside a camp for people displaced by earlier attacks near Makurdi, the capital of Benue state, according to local officials.
Security is a major issue in Nigeria ahead of next month's elections to replace President Muhammadu Buhari, a former army general.