At this point, the 9th Division's advance began to be hampered by a lack of supplies which, along with the rugged terrain, resulted in slow progress. It was not until 9 September that they reached the Busu River. The 2/28th Infantry Battalion was leading the Australian advance at this stage and the soldiers waded across. The current was strong and many of the men – 13 of whom drowned – were swept downstream. Nevertheless, the 2/28th was able to establish a beachhead west of the river. At this point, heavy rain began to fall again, and the river rose once more, preventing any other units from crossing. This effectively isolated the single Australian battalion, which was then subjected to repeated attacks by the Japanese. On 14 September, the 26th Brigade was able to force its way across and the advance continued. Along the coast the 24th Brigade was held up by a determined Japanese defence in front of the Butibum River, which was the final crossing before Lae. The stream was finally forded on 16 September, by which time Lae had fallen to troops from the 7th Division.