The African Union, European Union, and United States called Thursday for an immediate ceasefire and constructive dialogue between warring factions in Sudan. The groups also called for an end to tension between Somalia and Ethiopia over an agreement signed between Ethiopia and Somalia’s breakaway region Somaliland. Representatives of the groups, who spoke in Kampala, Uganda, after the meeting of an East African regional bloc, said that the two crises are threatening regional stability in the Horn of Africa. Sudan’s armed forces and the rivalRapid Support Forces have been fighting for control of…