Three brigades (eight infantry battalions and three artillery batteries) were put into action between July and September. During June and July, Mukti Bahini had regrouped across the border with Indian aid through Operation Jackpot and began sending 2000–5000 guerrillas across the border, the so-called Monsoon Offensive, which for various reasons (lack of proper training, supply shortage, lack of a proper support network inside Bangladesh) failed to achieve its objectives. Bengali regular forces also attacked BOPs in Mymensingh, Comilla and Sylhet, but the results were mixed. Pakistani authorities concluded that they had successfully contained the Monsoon Offensive, which proved a near-accurate observation.