ABUJA, Nigeria (AP) — At least 20 people have been killed during simultaneous attacks by unidentified gunmen on several communities in Nigeria’s north-central Benue state, police said on Tuesday.

The attacks occurred late Sunday in communities within the Gwer West and Apa areas, said Udeme Edet, spokesperson for the Benue police.

Edet said 12 people were killed in Apa and 10 in Gwer West, but local reports suggest the death toll may exceed 30. Five people who survived the attacks are currently receiving medical treatment in a local hospital, she added.

Nigeria’s police often provide lower death tolls than local authorities and witnesses when reporting on attacks.

Paul Biam, chief of staff to Benue Gov. Hyacinth Alia, visited the communities Monday and said the administration is doing all it can to prevent attacks in the state.

The Gwer West and Apa areas of Benue state have witnessed an uptick in attacks in recent months. Last week, gunmen killed at least 20 people in an attack on the village of Aondona, in Gwer West.

While it remains unclear who was responsible for the killings, such attacks are common in Nigeria’s northern region, where local herders and farmers often clash over limited access to land and water.

The farmers accuse the herders, mostly of Fulani origin, of grazing their livestock on their farms and destroying crops. The herders insist that the farms are on grazing routes that were first backed by law in 1965, five years after the country gained its independence.