On March 25, 1971, Pakistan Army cracked down on the Bengali population of the then East Pakistan. They massacred the capital of the East Pakistan that enraged the Bengali military officials of Pakistan Army who revolted against their authority and joined the Bangladesh Liberation War. The officials of the 2nd East Bengal Regiment situated in the Joydevpur Cantonment adjacent to the capital Dhaka also revolted with other regiments and left the cantonment on March 28, 1971 under the leadership of K M Shafiullah. Major Shafiuallah was initially selected as the Sector-3 Commander. Later, at the end of June considering the need of regular brigades to intensify the war against Pakistan Army the Provisional Government of Bangladesh decided to set up three brigades under the leadership of Major Ziaur Rahman, Major Khaled Mosharraf and Major K M Shafiullah.
Formation
K M Shafiullah, once the Second-in-Command of 2nd East Bengal Regiment was given the charge to set up a brigade in September 1971. Major ANM Nuruzzaman replaced him as the new Sector Commander of Sector-3. K M Shafiullah reorganized the two battalions of freedom fighters he had with him who were fighting in Sector-3 to form a brigade that is popularly known as S Force. The two battalions were the 2nd East Bengal Regiment and the 11th East Bengal Regiment. In addition, he added some 1200 new recruits to fulfill the mandatory manpower a brigade needs to be formed after some initial selection process. The new recruits were trained under the new brigade for two months in a row. The headquarters of S Force was situated in Fatikchhara.
A Company Commander - Lieutenant Shamsul Huda Bacchu
B Company Commander – Captain Subid Ali Bhuyan
C Company Commander - Second Lieutenant Nazrul Islam
D Company Commander - Second Lieutenant Abul Hossain
B Company Officer - Second Lieutenant Kabir
Medical Officer - Lieutenant Moinul Hossain
Major operations
S Force was ready for battle by the last week of November. It operated operations in Akhaura, Mukundpur, Dharmaghar and many in many other places from the last of November till the independence of Bangladesh.