At least five civilians were killed and 17 others injured Thursday when an explosive-laden motorbike detonated amid a crowd in eastern Afghanistan, an official said."The incident occurred in Baraki Barak district of Logar province. Five, including a women and a child, were killed," said Din Mohammad Darwish, a spokesman for the provincial governor.According to spa, all the victims were civilians, he said. However, it was not clear who had been the intended target.No one has taken responsibility for the attack.