The Indian Army is the largest branch of the Indian Armed Forces and is responsible for land-based military operations. Its primary mission is the National Security and Defense of India from external aggression and threats, and maintaining peace and security within its borders. It also conducts humanitarian rescue operations during natural calamities and other disturbances. The Indian Army is one of the three services under the Ministry of Defence. The President of India is the Commander-in-Chief of the Indian Armed Forces, and thus of the Indian Army. The highest ranking military officer is the Chief of Army Staff (COAS), who is also a member of the Chiefs of Staff Committee. The Indian Army came into being at the Independence of India in 1947, and inherited most of the regiments and infrastructure of the British Indian Army that were located in post-partition India.