Sudan will not enter negotiations with Ethiopia to resolve their escalating border dispute before Addis Ababa recognises farmlands long settled by Ethiopians as Sudanese territory, Sudan’s head of state said. Gen Abdel Fattah Al Burhan also accused Ethiopia of breaching Sudanese territory over the past two weeks by stationing forces in the border area of Baraka. "It is an unjustified escalation and an act of aggression against the country," he told members of the Sudanese armed forces in Khartoum. He called on Ethiopia to pull back its forces. Gen Al Burhan's comments, released by the Sudanese military’s media office late on Wednesday, signal a significant toughening of Sudan’s position on the dispute, which has led to a series of deadly clashes between the two sides after the Sudanese military moved late last year to wrest back control of some of the border enclaves settled by Ethiopians. The two nations accuse each other of massing troops in the area and of inciting unrest in each other's territory, raising the prospect of war. Mediation attempts have yielded no tangible results. Sudan previously called on Ethiopia to come to the negotiating table, arguing that the border was demarcated by a 1902 treaty affirmed in 1972, and that all that was needed was agreement on the location of border signs. Ethiopia said it would not negotiate until Sudan pulled back forces from the areas they took back since December, a condition rejected by Khartoum. The border enclaves have been settled since the 1950s by members of Ethiopia’s powerful Amhara ethnic group and allied militiamen. They are widely believed to include some of the most fertile farmlands in Sudan, which allowed the settlers to stay under an informal agreement. “There will be no negotiations with the Ethiopians without an acknowledgment first that those lands are Sudanese,” said Gen Al Burhan, also the country’s top soldier. The border issue comes at a time when Sudan is in dispute with Ethiopia over the enormous hydroelectric dam Addis Ababa is building on the Blue Nile. Sudan and fellow downstream nation Egypt want Ethiopia to enter a legally binding agreement on the filling and operation of the dam and on mechanisms to resolve future disputes. Without such agreement, Khartoum maintains, Sudan’s eastern region would be vulnerable to destructive flooding and the disruption of its own power-generating dams on the Blue Nile. Egypt fears that the dam would affect its share of the Nile waters, which supply more than 90 per cent of its fresh water needs. Ethiopia proposes guidelines, rather than a legally binding deal, to address the concerns. It said it intends to go ahead with a second and much larger filling of the dam this summer regardless of whether a deal is reached with Sudan and Egypt. Ethiopia is home to the source of the Blue Nile, the Nile’s main tributary that contributes more than 80 per cent of the river’s water. It meets the White Nile in Khartoum before they travel together north through Egypt to the Mediterranean. Ethiopia's foreign minister said on Wednesday that the country would not allow other nations to dictate how it uses the Blue Nile. The river “is the natural resource of all Ethiopians. No one can deprive Ethiopia of its 86 per cent share of the Nile" waters, Demeke Mekonnen said at a seminar marking 10 years since the start of construction on the Grand Ethiopian Renaissance Dam project. His comments drew sharp rebuke on Thursday from Egypt, which said they laid bare once again Ethiopia’s “intention and desire” to impose a fait accompli on Egypt and Sudan. “Egypt rejects that because it represents a threat to the interests of the people of Egypt and Sudan and because of the impact of such unilateral actions on regional stability and security,” said Foreign Ministry spokesman Ahmed Hafez. “It is regrettable that Ethiopian officials use the language of sovereignty when they speak of exploiting a transnational river,” he said. “International rivers are jointly owned by their littoral states and should not be subject to sovereignty or attempts to monopolise them.”