Nigerian children traumatised after their abduction need urgent and specialised help to recover from their ordeal, UN experts say.

Their statement comes a day after 279 girls were released following their recent kidnapping from a school in north-western Zamfara state.

It was the third school kidnapping since December in northern Nigeria by criminal gangs known to demand ransoms. In all three cases the pupils have now been freed.

“Social inclusion of these children requires the provision of long-term measures aimed at restoring their physical and psychological well-being,” the experts said.

They pointed to the mass kidnapping in December at a boys boarding school in Kankara in Katsina state as an example of how things had gone wrong.

“There has still not been an impartial, independent investigation into the abductions nor specialised rehabilitation for the children after the incident," they said.

“Due to such incidents, many children have not returned to class and some schools have already closed down in the border areas out of fear of reoccurrence. This may mean an end to education for these children.”

Kidnapping is a widespread criminal enterprise in Nigeria - and happens on an almost daily basis.

The UN experts said this was of particular concern when it came to abducted women and girls.

“We are alarmed at reports that an unknown number of women and girls have been abducted in recent years, and subjected to domestic servitude, forced labour, sexual slavery through forced marriages, forced and unwanted pregnancies.”

They reminded the Nigerian government that it had international legal obligations to protect the right to life, liberty and security of a person “as well as the obligation to adopt effective measures and policies to prevent exploitation”.