The UN chief "condemns strongly" the recent attacks by rebel forces in Sudan's Darfur province, and calls for an end to the fighting, fearing it could hamper regional peace efforts, his spokesman said.
Secretary General Ban Ki-moon "has expressed his grave concern at the outbreak of fighting on the outskirts of Khartoum as a result of the reported attacks by Justice and Equality Movement (JEM) forces against the capital," Michele Montas said in a statement.
"He condemns strongly the use of armed force and military means by JEM ... And calls for an immediate cessation of fighting," he said.
The UN chief, Montas added, "has expressed his anxiety at the effect (JEM fighting) would have on the overall situation in Sudan, as well as on the Comprehensive Peace Agreement and Darfur Agreement, and at the possible effect on civilian lives and property of any escalation of such attack."
The statement came as Sudanese authorities said that the army had repulsed an unprecedented attack on the capital Khartoum by Darfur rebels, following heavy clashes and the imposition of an emergency curfew.
"The operation is a failure," senior National Congress Party member Kamal Obeid told AFP after troops clashed with Islamist rebels across the river from Khartoum in its twin city of Omdurman, where witnesses had reported heavy fighting.