Hundreds of people have been killed or maimed by landmines in north-east Nigeria, research shows.

Mines laid by Boko Haram, the extremist group that has waged a deadly insurgency in the Lake Chad region, killed 162 people in two years and wounded 277 more, according to the Mines Advisory Group (MAG), a landmine clearance charity.

Casualties rose from 12 per month in 2016 to 19 per month in 2017-18, making Nigeria’s casualty rate from mines the eighth highest in the world.

After nine years of the insurgency, locally produced landmines, unexploded bombs and improvised explosive devices are scattered across the north-east.

“All around here people are dying. Just looking for firewood is very risky,” said Saleh Ibrahim, the deputy leader of a camp in Ngala, in Borno state, that shelters more than 100,000 people.

“Last November, five girls between eight and 17 years old found a metal ring on the ground. Two were young daughters of my sister. They thought it might be jewellery. One picked it up but it was linked to a bomb. They all died.”

MAG’s Avishek Banskota, who is based in Maiduguri, said: “Everyone I have met in Borno state has been affected in one way or the other, whether losing a family member, a friend or a house. People can’t move around freely in most of the region and much of the land can’t be used to farm or collect firewood, so the impact on communities is huge.”

According to the police, militants use pipes, pots and other items to make their own munitions and harvest explosives from undetonated ordnance. One officer said the militants tended to plant items in areas where they thought the army would visit, and also mined around their bases in remote areas.

Boko Haram splintered into several groups in 2016 but its factions still wield considerable power. Abubakar Shekau, the longtime leader of the group who pledged allegiance to Isis, was rejected by the latter in favour of Abu Musab al-Barnawi, the son of the group’s founder, possibly because Shekau had been targeting Muslim civilians. Barnawi’s faction is perceived to be primarily targeting Christians and the military, while Shekau’s indiscriminately abducts, rapes and kills.

However, there are indications that Barnawi’s group, Islamic State West Africa Province (ISWAP), is becoming more extreme. Mamman Nur, a more moderate leader, was reportedly killed by his own men in August.

The MAG data suggests more mines have been laid in the south of the region, where Shekau’s group mostly operates, though the figures may be skewed as the north, where ISWAP operates, is less accessible.

The data may show only a fraction of the landmine problem. The military does not share information about how many mines it clears and refuses to allow access to much of Borno state. Humanitarian organisations are not allowed in areas not controlled by the military, and 900,000 people are thought to be stuck in these areas without adequate food or healthcare.

The Nigerian authorities have been sending thousands of people back to garrison towns in unsafe areas, where they run the risk of Boko Haram attacks, in an apparent attempt to show they have secured the north-east before next year’s presidential election. Many of those who have returned have regrets. Some are not even originally from the areas to which they are moving.

It is unclear at what rate Boko Haram is still laying mines. This month the military bombed what it described as an IED factory in Guzumala.

MAG is launching a campaign to raise awareness of the landmine situation in Nigeria. “Despite hundreds of people being recently killed or injured by landmines in Nigeria, the issue has largely gone under the radar,” said Chris Loughran, the organisation’s director of policy and advocacy.

“We are writing to Kate Osamor, the chair of the UK’s parliamentary group for Nigeria, asking her to make a statement in the House of Commons urgently calling for this new landmine crisis to be included as a humanitarian response priority by the international community.”