During the night of 19/20 February, the Imperial Japanese Army's 228th Regimental Group, began landing in Portuguese Timor. The first contact was at Dili, the capital of Portuguese Timor, where the Allies were caught by surprise. Nevertheless, they were well-prepared and after inflicting heavy casualties on the troops attacking the airfield, the garrison destroyed the airfield and began an orderly retreat towards the mountainous interior and the south coast. On the same night, Allied forces in West Timor were under extremely intense air attacks, which had already caused the RAAF force to be withdrawn to Australia. Sparrow Force HQ was immediately moved further east, to its supply base at Champlong, and soon lost contact with the 2/40th.