MAIDUGURI, Aug 14 (Reuters) - Attackers killed 22 commuters on a road near the capital of Nigeria"s Plateau state, a morgue attendant told Reuters, in the latest outbreak of violence across Africa"s most populous nation in which scores of civilians have been killed this year. Armed attackers have increasingly targeted Nigeria"s roads and unrest has been roiling several regions. read more In Jos, capital of Plateau state in the country"s middle belt, a morgue attendant who asked to remain anonymous said security forces had brought 22 bodies to the hospital on Saturday. A military spokesman said in a statement that troops had responded to a distress call on Rukuba road in the Jos North local government area and had arrested 12 suspects, after an unspecified number of people were killed and injured. It appealed for further information and said it had stepped up security patrols in the area. Elsewhere three children in northeastern Borno state were killed by unexploded ordnances left on a bridge, according to Unicef. Two children sustained mild injuries and three others were in critical condition. Unicef said unexploded ordnance are small enough to pick up or kick around, putting children, who can mistake them for toys or objects of value, at particular risk. In Plateau state Governor Simon Bako Lalong said in a statement he would not allow any form of lawlessness to disrupt the state, and commended security agencies for their quick response. His statement did not specify the number killed. A police spokesperson said they would issue a statement later and declined to comment further. Conflicts between farmers and cattle herders in the middle belt have killed thousands of people and displaced half a million over the past decade, according to French medical charity Medecins Sans Frontieres. A 12-year war against Islamist militants in northeast Nigeria meanwhile has killed an estimated 350,000 people and displaced millions. read more Reporting by Maiduguri newsroom and Lanre Ola Additional reporting by Tife Owolabi Writing by Libby George Editing by David Holmes Our Standards: The Thomson Reuters Trust Principles.