Violent extremists in Nigeria have killed 110 farmers in a horrific attack that Nigerian President Muhammadu Buhari called insane. The death toll is expected to rise even further.

As the farmers were at work in their rice fields, in the village of Koshobe and other rural communities in the Jere area near Maiduguri, the capital of Borno state, extremists on motorcycles rounded them up, bound them, and then slit their throats officials said.

Armed men on motorcycles led a brutal attack on civilian men and women who were harvesting their fields,” Edward Kallon, the UN’s humanitarian coordinator in Nigeria, said in a released statement.

“At least 110 civilians were ruthlessly killed and many others were wounded in this attack,” he said, adding that 15 women are believed to have been kidnapped.