Gunmen have killed at least 29 people in north-east Nigeria, a state governor said on Monday, with local people saying the attackers targeted young people gathered at a football pitch, the latest bout of deadly unrest in Africa’s most populous nation.

The attack on Sunday occurred in Adamawa state, which borders Cameroon, and is a hotspot for violence by jihadists and criminal gangs. Communal violence over conflict for land is also rife in the state.

The latest attack comes as Nigeria’s security crisis is increasingly under scrutiny both abroad and at home as general elections are less than a year away.

Ahmadu Umaru Fintiri, the governor of Adamawa state, visited the scene of Sunday’s attack and “confirmed that no fewer than 29 people were killed in a deadly attack on Guyaku community in Gombi local government area”, his spokesperson said in a post on social media.

Local people also gave a similar toll.

Philip Agabus, a local resident, told Agence France-Presse: “Our people converged at a football pitch in Guyaku community ... [and] were attacked by insurgents who entered with guns and began shooting randomly.”

The dead were “youths, including some ladies that were watching football”, another resident, Joshua Usman, told AFP. “They also burned places of worship, houses and motorcycles.”

The state governor’s office wrote: “The attackers operated for several hours, killing dozens of residents, burning places of worship, and destroying property including motorcycles.” It cited a local community leader, Aggrey Ali.

Local television showed footage of a burnt church and several charred motorcycles.

The governor blamed the Boko Haram militants who are active in the north-east of Nigeria.

But a rival group, the Islamic State’s West Africa Province (ISWAP), claimed responsibility for the attack saying it “killed at least 25 … Christians” and “torched a church and nearly 100 motorcycles”, in a statement reported by the SITE monitoring group.

Fintiri condemned the attack, saying “it will not go unpunished” while he vowed “intensifying security operations immediately to restore peace”.

Since 2009, the jihadist insurgency in Nigeria, led primarily by Boko Haram and the ISWAP, has left tens of thousands of people dead and millions displaced in the north-east of the country, according to the United Nations.

The jihadist conflict has spread to neighbouring Niger, Chad, and Cameroon.

Nigeria is now looking to the US for technical and training support for its troops fighting the jihadists after a resurgence of violence strained relationships between the two countries.

A separate attack occurred on Sunday in another district more than 100km away, which a local community blamed on farmland disputes in several villages in the Lamurde area.

Bulus Daniel, a local government council chair for the Lamurde area, told AFP: “Lives were lost; properties were also lost.”

Meanwhile, Nigerian security forces rescued 15 pupils after gunmen abducted 23 children and the wife of a school proprietor during an attack at the weekend on an unregistered orphanage and school in central Nigeria’s Kogi state, the state government said.

Kingsley Femi Fanwo, the Kogi state commissioner for information, confirmed that 15 pupils have been rescued and that efforts were ongoing to secure the release of the remaining victims.

School kidnapping is thriving in most parts of Nigeria because security is weak and perpetrators demand ransom before they release their victims.

Mass kidnappings, despite repeated government pledges to prevent such incidents, continue to disrupt education, commerce and travel, leaving frustrated residents questioning the authorities’ effectiveness in addressing the threat.

Additional reporting by Reuters