UNICEF is warning that up to 50,000 children in the country's north-east are in danger of starving to death. The UN is calling for increased humanitarian aid, but insecurity in the region is hampering its efforts.

Some of the latest images to emerge from the north-eastern state of Borno. Islamist group Boko Haram has waged a seven-year insurgency here, it's losing ground, but it's leaving behind a dreadful legacy.

And Unicef says the full extent is only now emerging.

"This has been a very silent crisis. The number of people displaced in Northern Nigeria, from North East Nigeria because of the conflict is actually the 3rd biggest displacement crisis in the world but it is almost a secret, people have not been paying attention to it. There's obviously a lot of competition at the moment in the world for resources," said Doune Porter, UNICEF.

The Boko Haram troubles have left more than two million people needing aid. Almost a quarter of a million children in Borno are suffering from malnutrition and one in five of those could simply starve to death - unless help comes soon. But Unicef says it's still too risky to go in.

"Accessibility for security reasons is definitely still one of the problems. The territory is no longer controlled by Boko Haram but it's not safe to travel and there are lots of attacks on the roads, land mines as well so, many of this areas are still inaccessible for security reasons," said Doune Porter, UNICEF.

The government has been painting a picture of near normalcy in the north east but the scale of unfolding humanitarian crisis is a stark contradiction to that claim, UNICEF is says it urgently requires $55 million dollars to avert further deaths of children and bring bring a quarter of a million children out of acute malnutrition.