For military purposes, Bangladesh was divided into 11 sectors under 11 sector commanders. In addition to these sectors, later in the war, three special forces were formed: Z Force, S Force and K Force. These three forces' names were derived from the initial letters of the commander's name. The training and most of the arms and ammunitions were arranged by the Meherpur government which was supported by India. As fighting grew between the Pakistan Army and the Bengali Mukti Bahini, an estimated ten million Bengalis, mainly Hindus, sought refuge in the Indian states of Assam, Tripura and West Bengal.