Seventy-three people killed since the start of the year in communal violence between semi-nomadic herdsmen and farmers were buried in Nigeria on Thursday highlighting a bloody conflict over fertile land that is taking on political significance.

The mass burial took place in Makurdi, in the central state of Benue, where thousands of mourners took to the streets to watch the funeral procession. The killings occurred in remote parts of Benue, the state worst hit by clashes that have killed at least 83 people since Dec. 31.

Thousands of herdsmen mainly from the Fulani ethnic group have moved southward in the last few years to flee spreading desertification in the north, putting pressure on dwindling fertile land amid rapid population growth.