The UN World Food Program (WFP) said Tuesday its racing against time as it conducts a series of urgently needed airdrops of food assistance to remote areas of South Sudan. The WFP said in a statement that it's using a combination of airdrops and airlifts, in which the aircraft lands and is unloaded, to get vital food supplies to remotest areas which are inaccessible because of insecurity and other obstacles. "Insecurity, border restrictions and other barriers to humanitarian access are causing serious problems for WFP moving food into and around the country at a time when the agency is urgently trying to deliver food assistance to support hundreds of thousands of people in need," the WFP said in a statement issued in Nairobi. The UN food agency launched the operation to feed people affected by conflict and to resupply isolated refugee camps where food stocks have dwindled. WFP Country Director Chris Nikoi said the internally displaced people (IDPs), refugees from neighboring Sudan, and conflict- affected communities around South Sudan are also receiving food supplies. "We are in a race against time to get assistance to people who are in critical need in places we simply haven't been able to reach by road or river," said Nikoi. Nikoi said given the level of conflict, the WFP had prepared to move some food by air to some parts of the country, particularly during the rainy season. "But we have faced more difficulties than envisioned and now need to deliver more food by air than planned," he said. The agency said two rounds of airdrops on Tuesday delivered enough cereals for about 8,000 displaced people for 15 days in the town of Ganyiel in Unity state, following a trial run of airdrops in recent days in Maban County in Upper Nile state. Airdrops are planned for nine locations in Upper Nile, Jonglei and Unity states, and may be expanded to reach other areas, adding that the WFP plans to pre-position food before the rainy season makes more than half the country inaccessible by road. The WFP, working closely with the UNHCR, is also supporting a rapidly growing number of South Sudanese refugees who have fled to neighboring countries. According to the WFP, over 210,000 refugees from South Sudan have arrived in Ethiopia, Kenya, Uganda and Sudan since the crisis began. "We are concerned about reports of alarmingly high rates of malnutrition among children arriving at refugee camps in neighboring countries, particularly Ethiopia," WFP Regional Director for East & Central Africa Valerie Guarnieri said. "While we are working with partners to provide specialized nutritious foods for refugee children, the high levels of malnutrition are a sign that the humanitarian situation in inaccessible regions of South Sudan may be rapidly deteriorating." The WFP said transporting food across the border overland from Ethiopia and Sudan is key to supplying conflict-affected areas of South Sudan. The agency vowed to continue working with all parties to the conflict and with neighboring country governments to resume reliable movement of humanitarian goods, including cross-border shipments. The WFP aims to scale up its assistance to support 2.5 million conflict-affected and food-insecure people in South Sudan over the coming months. Since the conflict begun in mid December last year, the WFP has provided lifesaving food assistance and nutrition support to around 765,000 people.