Bama - Nigeria has pledged to do more to tackle food shortages among people made homeless by Boko Haram, as the United Nations warned about 50 000 children could starve to death this year in one northeastern state alone.Medical charity Doctors Without Borders (MSF) has also warned "a catastrophic humanitarian emergency" was unfolding at the camp for internally displaced people (IDPs) in Bama, Borno state. At least 188 people died between May 23 and June 22, mainly from diarrhoea and malnutrition, while more than 1 200 graves, many of them for children, had been dug near the camp in the last year, MSF said last week. A Nigerian government delegation visited Bama on Thursday to see conditions for the 25 000 people living there. Maryam Uwais, special advisor to President Muhammadu Buhari for social protection, described it as "an overwhelming situation for any government to handle"."The state government has done its best. We came to see things for ourselves. We will go back and make reports and soonest there will be some relief, more relief coming this way."'Desperate conditions' Domestic and international aid agencies rely on the military to drive the 70km from the state capital Maiduguri to Bama, which was liberated in March last year. Roads in to and out of Maiduguri are nominally open, but vehicles are still vulnerable to attack from the Islamist militants, who have been pushed into the bush by the military since January 2015. Many displaced people from in and around Bama are currently staying in camps and host communities in Maiduguri. MSF's claims angered the Nigerian government and Borno state health commissioner Haruna Mshelia dismissed reports of severe acute malnutrition at the Bama camp as exaggerated. But he said some 1 800 of the most vulnerable had been evacuated to Maiduguri for special treatment and feeding. The United Nations said in a statement Thursday its agencies and partners in northeast Nigeria were "reporting high levels of severe malnutrition and desperate conditions" in recently liberated areas. "Improving security has enabled humanitarians to access areas that were previously cut off," said acting UN humanitarian coordinator for Nigeria Munir Safieldin."The conditions we are seeing there are devastating," he added, urging "a much faster and wider response".'Severe acute malnutrition' More people in urgent need of assistance are being found as hard-to-reach remote locations are opened up and Unicef Nigeria representative Jean Gough had a stark warning if nothing was done. "We estimate that there will be almost a quarter of a million children under five suffering from severe acute malnutrition in Borno this year," she said in a statement. "Unless we reach these children with treatment, one in five of them will die. We cannot allow that to happen." The seven-year Boko Haram insurgency has killed at least 20 000 people and displaced more than 2.6 million, with a new influx heaping pressure on local authorities. Food insecurity and malnutrition has reached emergency levels, the Nigerian government said on Monday, and more than 500 000 people require immediate food assistance. The violence has left communities destroyed and farmland devastated, also hitting the supply of food to markets, driving up costs for people already robbed of their livelihoods.