Operatives of the INA were also landed in the Indian coast by submarine for planned espionage operations within India. This first incarnation of the Indian National Army was involved in operations of espionage in the Burma frontier which, according to some military historians and allied generals, threatened the morale of Indian troops and fed discontentment and was partly responsible for the failure of the first Burma offensive. A large number of the INAs initial volunteers, however, later went on to join the INA in its second incarnation under Subhas Chandra Bose. The unit was dissolved in December 1942 after apprehensions of Japanese motives with regards to the INA led to disagreements and distrust between Mohan Singh and INA leadership on one hand, and the League's leadership, most notably Rash Behari Bose, who handed over the Indian National Army to Subhas Chandra Bose. It was formally proclaimed in April 1942 and declared the subordinate military wing of the Indian Independence League in June that year. It was formed with Japanese aid and support after the Fall of Singapore and consisted of approximately 12,000 of the 40,000 Indian prisoners of war who were captured either during the Malayan campaign or surrendered at Singapore and was led by Rash Behari Bose. The First Indian National Army (or the First INA) was the Indian National Army as it existed between February and December 1942. For its successor unit formed under Subhas Chandra Bose, see Indian National Army. This article is about the unit formed under Mohan Singh that existed up to December 1942.