Nearly 200 refugees fleeing Boko Haram militants have starved to death over the past month in Bama, Nigeria, the medical charity MSF says.

A “catastrophic humanitarian emergency” is unfolding at a camp it visited where 24,000 people have taken refuge.

Many inhabitants are traumatised and one in five children is suffering from acute malnutrition, MSF says.

The Islamist group’s seven-year rebellion has left 20,000 people dead and more than two million displaced.

Nigeria’s military has carried out a large-scale offensive against them but Boko Haram still attacks villages in the north-east, destroying homes and burning down wells.

Displaced people in Bama say new graves are appearing on a daily basis, according to a statement from MSF.

It quoted inhabitants as saying about 30 people died every day due to hunger or illness.

Although the area has been unsafe to travel through, MSF says one of its teams reached Bama on Tuesday.

It went in with a military convoy from the city of Maiduguri in Borno state.

“This is the first time MSF has been able to access Bama, but we already know the needs of the people there are beyond critical,” said Ghada Hatim, MSF head of mission in Nigeria.

“We are treating malnourished children in medical facilities in Maiduguri and see the trauma on the faces of our patients who have witnessed and survived many horrors,” he said.