NEW YORK ( CNN ) -- The number of deaths in Sudan 's Darfur region since 2006 may have been underestimated by as much as 50 percent , the U.N. undersecretary-general for humanitarian affairs said Tuesday . An man injured in clashes with tribal fighters outside the African Union Mission in southern Darfur in 2007 . In March , international figures , including U.N. data , put the death toll in Darfur at 200,000 , with another 2.5 million people displaced . But 300,000 are believed to have died in the tribal conflict in the past two years , said John Holmes , who also is the United Nations emergency relief coordinator . Holmes said that sexual violence has increased and that food allotments for civilians affected by the civil war will be halved in a few days . Holmes gave the U.N. Security Council an update on conditions in the western Sudan region , revisiting a report he gave a year ago . `` I am sad to say that the humanitarian situation remains as grim today as it was then , if not more so , '' he said . In 2008 , 100,000 civilians have fled their homes , many not for the first time . The Darfur conflict began five years ago , when ethnic African tribesmen took up arms , complaining of decades of neglect and discrimination by the Sudanese government . Sudan 's Arab-dominated government is accused of responding by unleashing tribal militias known as Janjaweed , which are said to have committed the worst atrocities against Darfur 's local communities . There also have been intra-rebel and tribal clashes , Holmes added . He blamed the military arm of the Justice and Equality Movement faction of the Sudan Liberation Movement for the most recent round of violence , and he accused the government of using `` disproportionate force '' and failing to differentiate between civilians and rebels in their response . `` Darfur today is still characterized by insecurity , lawlessness and impunity , '' he said . `` A particularly worrying feature is evidence of high levels of sexual violence and exploitation in the northern corridor of west Darfur over the past two months . '' This is shown by the increased number of women and girls seeking treatment after sexual brutality , Holmes said . The World Food Programme announced last week that it will have to cut back its food distributions in May , partly because of attacks on convoys that reduced the amount of supplies they can get through , Holmes said . Six aid workers have been killed this year , and 42 humanitarian posts have been attacked . The supply line also is hurt by soaring food prices : The price of staples such as millet has doubled since April 2007 , Holmes said . While expressing gratitude to the Sudanese government for improved cooperation under various agreements , Holmes said there still is no physical access to internally displaced persons and some other groups . He said he was `` saddened and angry '' that after five years , there has been no lasting solution to the suffering . He made several recommendations to the government , including disbanding the Janjaweed , providing security for citizens , ending impunity for criminals and shouldering more of the financial burden for humanitarian aid . Holmes also said rebels must stop their attacks against people and humanitarian convoys . E-mail to a friend .
In March , death toll in Darfur given as 300,000 ; 200,000 people displaced . United Nations official now says that figure is closer to 300,000 dead since March . Official reports that sexual violence has increased , food rations hurt in region . Darfur conflict began 2006 when ethnic African tribesmen took up arms .