Sri Lanka pushed on with an offensive on Friday to win control of a waterway from Tamil Tiger rebels, as calls mounted for an independent probe into the killing of 17 aid workers in the midst of the fighting. The military said it exchanged intermittent artillery and mortar fire with the Tigers as the fighting, the worst since a 2002 ceasefire, entered a 17th day. But the army said the intensity was far lower than previous days. Full Story