At least four people got injured when a fire at a munitions dump sparked a wave of explosions outside the southern Sudanese capital of Juba on Friday, witnesses and U.N. staff said. The fire caused intermittent explosions for about 90 minutes from 4 p.m. (1300 GMT) and sent a plume of smoke into the air on the edge of Juba, where the government of southern Sudan is based. However, the cause of the fire was not immediately established. Speculation on whether this explosion was an attack was cleared by a spokesman for the former rebel Southern People's Liberation Movement (SPLM) who went on local radio to reassure residents it was not an attack.