Juba - An advanced party of Chinese peacekeepers is in South Sudan and the rest of the 700-strong contingent is due to arrive by early April, a UN official said on Friday, part of a surge in a UN mission to protect civilians in a nation mired in conflict.Fighting in the oil-producing nation, which is one of the world's poorest, has killed more than 10 000 people, driven more than a million from their homes and left many without enough food."We had an advanced party of 18 members of the incoming battalion arrive on 9 January to begin preparations for delivery of contingent-owned equipment," said Brian Kelly, a spokesman for the UN mission in South Sudan UNMISS.He said some of the equipment had already landed in Entebbe, in neighbouring Uganda."Overall deployment of the 700-stong Chinese infantry battalion and its equipment will take more than two months to complete," he said, adding 180 troops would be in Juba by the end of February with 520 more arriving by late March or early April.China is a major investor in South Sudan's oil industry.Fighting erupted in December 2013 in South Sudan, which won independence from Sudan in 2011, after months of political tension between President Salva Kiir and his sacked deputy and political rival, Riek Machar.The conflict has reopened deep tensions among ethnic groups, pitting Kiir's Dinka against Machar's Nuer.Some of the worst fighting in the nation of 11 million people has been in Jonglei state and the two oil producing states of Unity and Upper Nile.Linda Etim, USAID deputy assistant administrator for affairs, said on Friday nearly half of the population in those three areas was projected to face a food security emergency."The malnutrition situation is classified as critical or very critical in more than half of the country," she said.Although the warring parties have agreed to ceasefires -- the first deal reached in January 2014, a month after fighting erupted -- the deals have been regularly flouted. Fighting has picked up after a lull during rains that ended late last year.In Beijing, Foreign ministry spokesperson Hong Lei said the peacekeepers were "in the process of gradually being deployed," without giving more detail.