Blast near U.S. embassy in Kabul was accident, Afghan official says --- (Reuters) - An accidental detonation of explosives stored in an Afghan facility beside the U.S. embassy in Kabul sparked a brief panic early on Thursday, triggering concerns of an attack, but no immediate reports of casualties. -- The blast happened about 10.30 a.m. (0600GMT), and the U.S. embassy's alarm was heard blaring across the diplomatic area of the Afghan capital immediately afterwards.-- But Farid Shamal, a spokesman for Afghanistan's National Directorate of Security, allayed the worries, saying an electrical fault had accidentally ignited explosives stored in the agency's main compound in Kabul. - More