Justin Welby has condemned the killing of at least 110 farmers in Nigeria by extremist group Boko Haram. 

The attack happened in the village of Koshobe and other rural communities in Borno State, where many farmers work on rice fields. 

On Sunday, authorities announced the killing of 43 people, but it has since been confirmed by United Nations (UN) that at least 110 people are dead.

Insurgents carried out the killings on the same day that many were casting their vote for the first time in 13 years to elect local government councils. 

In a tweet, the Archbishop of Canterbury has described the massacre as "an act of pure evil".

He said: "The massacre of rice farmers in Borno State was an act of pure evil. May God be with those who are traumatised and bereaved. 

"I pray fervently for justice, peace and security in Nigeria."

The attack has also been described by a United Nations official as "this year´s most violent direct attack".

In a statement, the UN official said: "I am outraged and horrified by the gruesome attack against civilians."

Nigerian President Muhammadu Buhari also expressed grief over the killings. 

"I condemn the killing of our hardworking farmers by terrorists in Borno State," he said. "The entire country is hurt by these senseless killings. My thoughts are with their families in this time of grief. May their souls rest in peace."