This is stated in a statement issued by the official representative of the head of the world organization, Stephane Dujarric.
"The Secretary-General calls on the leaders of the Sudanese Armed Forces and the Rapid Reaction Force to immediately cease hostilities, restore calm and begin a dialogue to resolve the current crisis," the statement said.
It is noted that Guterres "strongly condemns" the clashes between the Sudanese Armed Forces and the rapid reaction forces.
Earlier, Sudan's rapid reaction forces said that units of the country's army attacked their base in Khartoum.
The Sudanese army said it continues to control the presidential palace and other strategic facilities.