In the plateau state, at least 30 people were killed in clashes between herders and farmers. The US convoy was attacked in Anambra, where separatists have stepped up attacks.
In Nigeria, local officials say at least 30 people have died in clashes between herders and farmers on Monday.
Located in central Nigeria, Plateau State is in a region that divides the Muslim-majority north and the predominantly Christian south.
A state communications representative told AFP news agency that herders are often Muslim and farmers are mainly Christian.
According to the police spokesperson, the culprits are still being searched. The goal of the authorities was to ensure that the perpetrators were “neutralised” or, if possible, arrested.
A 24-hour curfew was imposed in the area to prevent the crisis from spreading to other areas.
There has been an increase in widespread crime involving heavily armed gangs in the northwestern and central parts of the country.
In April, about 50 people were killed when gunmen attacked a village in Benue state. Local authorities blamed herdsmen for the violence.
On Tuesday, gunmen killed four people traveling in an American motorcade in southern Nigeria’s Anambra state. In addition, the gunmen abducted three, among others reported AFP and Reuters.
Police representative Ikenga Tochukwu said two members of the mobile police and two employees of the US consulate were killed in the attack. No US citizens were among the victims. The attackers abducted two police officers and the driver from the convoy before security forces arrived.
According to news agencies, White House spokesman John Kirby confirmed the incident on Tuesday.
Separatist forces operating in the region have increased their attacks in recent years. The targets are often police and government buildings.
Nigerian authorities have blamed the attacks on the IPOB movement, which is pushing for the independence of Biafra. The movement has repeatedly denied being responsible for the violence.