The Battle of Bilin River was fought in February 1942, by the 17th Indian Infantry Division. The 17th Division held the Japanese at the Bilin River for two days of close-quarters jungle fighting. The Japanese tactics were to outflank, and eventually with encirclement imminent, they were given permission to fall back. The division disengaged under cover of darkness and began a retreat along the dusty track to the Sittang bridge. The Battle of Sittang Bridge followed after which 17th Division lost most of its artillery, vehicles and other heavy equipment. Its infantry manpower was 3,484 just over 40% of its establishment, though it was already well under-strength before the battle started. The Battle of Pegu in March was carried out by the surviving elements of the 17th Division and the 7th British Armoured Brigade, which had just arrived from the Middle East. In April, the Battle of Yenangyaung was fought between the 7th Armoured Brigade, 48th Indian Infantry Brigade and 1st Burma Division for control of the Yenangyaung oil fields. The Japanese suffered heavy casualties during the battle, but the Allied forces were too weak to hold the oil fields and had to retreat to the north. The fighting retreat to India, was successfully completed in May just before the monsoons would have cut them off. Approximately 12,000 of the 40,000 Indian prisoners of war who were captured either during the Malayan campaign or surrendered at Singapore were led by Mohan Singh as the First Indian National Army which was dissolved in December 1942.