Fighting erupted in Sudan\'s Blue Nile border state between the army and forces loyal to the elected governor Malik Agar, both sides said on Friday, less than two months after the secession of the south. The clashes follow a build-up of troops in Blue Nile and warnings that the three month-old conflict in nearby South Kordofan was likely to spill along Sudan\'s new international border with the south. \"In a new upsurge of aggression and in an extension of what happened in South Kordofan, forces allied to the Popular Defence Forces and the Sudanese Army instigated an all-out attack on the positions of the Sudan Peoples\' Liberation Army (SPLA) in Damazin\" early Friday, Agar\'s SPLM-North party said. The attacks targeted the residence of Agar, the chairman of the SPLM-North, Sudan\'s main opposition party, and the position of Al-Jundi Suleiman, commander of special joint units in Blue Nile state, at the entrance to Damazin, the state capital, according to the statement. Agar was unharmed, but the offensive was later intensified to include all SPLA positions, the statement added, without giving details of casualties. The SPLM-North said tensions had escalated in the past four days because of the Sudanese army\'s large-scale troop and weapons deployment in Damazin, which included 12 tanks and 40 trucks mounted with heavy machineguns. Army spokesman Sawarmi Khaled Saad confirmed that fighting had erupted in Blue Nile, but insisted the SPLA was responsible. \"Yesterday (Thursday) evening, at 9 o\'clock (1800 GMT), SPLA troops attacked army positions in Damazin,\" he told AFP, adding that attacks also took place in five other areas. \"Now we are in control of those areas, and our troops are pursuing the rebels,\" he said. \"What happened yesterday confirmed the statement by Malik Agar on August 28, when he called for the youth of Blue Nile to prepare for war,\" Saad added. The state minister for information, Sanaa Hamad, said the security forces had ordered the SPLM to hand over to the authorities all those involved in the clashes or face arrest. She also denied that Agar\'s house had been bombed, in a statement to the official SUNA news agency, adding that the governor was currently in the border town of Kurmuk. But an SPLM-North source said the former garrison town, a key battleground in the devastating 22-year war between Khartoum and the SPLA/M, the ex-southern rebels turned ruling party of the south, was bombed on Friday morning along with other SPLA positions in Blue Nile. Khartoum has sought to reassert its authority within its new borders in view of South Sudan\'s formal declaration of independence on July 9. Blue Nile and South Kordofan are both located north of Sudan\'s new international border, but have large numbers of SPLM supporters. Since early June, clashes in South Kordofan, Sudan\'s only oil-producing state, have pitted the Sudanese army against Nuba militiamen once allied to the southern rebels and now calling themselves the SPLA-North. President Omar al-Bashir on August 23 declared a two-week ceasefire, but his government has since been accused of failing to respect its pledge and has come under heavy criticism from the United Nations and human rights groups. The UN under secretary general for humanitarian affairs, Valerie Amos, said on Tuesday that more than 200,000 people affected by the fighting in South Kordofan faced \"potentially catastrophic levels of malnutrition and mortality\" because of Khartoum denying access to aid agencies. Also this week, two leading human rights groups said that deadly air raids on civilians in rebel-held areas of the Nuba Mountains may amount to war crimes.