Rebels in Sudan’s South Kordofan state said Friday they destroyed a military camp in a district capital, killing four soldiers after vowing to step up their efforts to overthrow the government.The attack against the Migreh camp occurred in Rashad, a town centre in northeastern South Kordofan, more than 400 kilometres (250 miles) from the Sudanese capital Khartoum, the Sudan People’s Liberation Movement-North (SPLM-N) said in a statement."Four enemy soldiers killed and the rest escaped,” the statement said.Sudan’s army spokesman could not be immediately reached for comment but both sides earlier reported there had been fighting in a rural area outside Rashad late last week and early this week.Rebels said their attack on the military camp was in retaliation for the burning and looting of a village by government forces.The army has accused SPLM-N rebels of "terrorising and intimidating” residents in the area.Access to the region is restricted, making verification of claims difficult.SPLM-N leaders last week held a "turning point” meeting in South Kordofan, agreeing to work more closely with Sudan’s political opposition, while intensifying co-ordination with rebels from the Darfur region, SPLM-N spokesman Arnu Ngutulu Lodi told AFP on Tuesday.Last year the SPLM-N and Darfur rebels formed a "Revolutionary Front” to overthrow the Arab-dominated Khartoum regime they say is unrepresentative of the country’s diversity.Ethnic minority insurgents of the SPLM-N were allies of southern rebels during Sudan’s 22-year civil war, which ended in a 2005 peace deal and South Sudan’s secession in July last year.Just before the secession, fighting began in South Kordofan between the rebels and the government. A similar conflict started in Blue Nile state one year ago this Sunday, September 2.Sudan accuses South Sudan of supporting the SPLM-N, a charge which analysts believe despite denials by the Juba government.Sudanese government figures released this week indicated that more than 8,700 people were uprooted in the Rashad area fighting, adding to more than 650,000 the United Nations says have been displaced or severely affected by the war in South Kordofan and Blue Nile.The UN has expressed concern for months about a worsening humanitarian situation in the war zone, where Khartoum has cited security concerns in tightly restricting the operations of foreign aid agencies.In early August both the government and rebels signed memorandums with the African Union, Arab League and UN to allow for humanitarian access throughout the two states -- including in rebel-held areas.However, there is no start date for the operation.Lodi accused the government of "delaying tactics” and said the rebels now want aid distributed through South Sudan and Ethiopia.A ruling party official insisted the government is committed to providing humanitarian assistance to all those affected by the fighting.