Immediately after the formation of the provisional government, Free India declared war against the Allied forces on the Indo-Burma Front. Its army, the Indian National Army ("Azad Hind Fauj"), went into action against the British Indian Army and the allied forces as part of the Imperial Japanese Army in the Imphal-Kohima sector. The INA had its first major engagement at the Battle of Imphal where, under the command of the Japanese Fifteenth Army, it breached the British defences in Kohima, reaching the salient of Moirang before suffering a catastrophic defeat as the Allied forces held, and Allied air dominance and compromised supply lines forced both the Japanese and the INA to retreat.