MSF says "a catastrophic humanitarian emergency" is unfolding at a camp in Bama, where 24,000 people have taken refuge.
Nearly 200 refugees, who fled Boko Haram attacks, have died of starvation and dehydration in the northeastern Nigerian city of Bama in the past month, Doctors Without Borders said on Wednesday.
The refugees "speak of children dying of hunger and digging new graves every day," according to a statement from the global medical charity group, also known by its French acronym MSF.
"A catastrophic humanitarian emergency" is unfolding at a makeshift camp on a hospital compound where 24,000 people have taken refuge, it said.
The doctors referred 16 emaciated children at risk of dying to their special feeding centre in Maiduguri. One in five of the 15,000 children are suffering severe acute malnutrition, the group found.
"We see the trauma on the faces of our patients who have witnessed and survived many horrors," said Ghada Hatim, head of the Doctors Without Borders mission in Nigeria.
Her team reached Bama on Tuesday following a military convoy from Maiduguri, the Borno state capital that is the headquarters of Nigeria's military campaign.
Though Bama is just 70km southeast of Maiduguri, ongoing clashes between the rebels and government troops make travel unsafe and farmers have not planted crops for 18 months, Dr Christopher Mampula of MSF explained by telephone from Paris.
The refugees in Bama are among 1.8 million Nigerians forced from their homes and living inside the country, with another 155,000 in neighbouring countries, according to the UN.