common defence against "northern" enemies (i.e. China), which was rejected by India, citing nonalignment. In 1962, President of Pakistan Ayub Khan made clear to India that Indian troops could safely be transferred from the Pakistan frontier to the Himalayas. But, after the war, Pakistan improved its relations with China. It began border negotiations on 13 October 1962, concluding them in December of that year. The following year, the China-Pakistan Border Treaty was signed, as well as trade, commercial, and barter treaties. Pakistan conceded its northern claim line in Pakistani-controlled Kashmir to China in favour of a more southerly boundary along the Karakoram Range. The border treaty largely set the border along the MacCartney-Macdonald Line. India's military failure against China would embolden Pakistan to initiate the Second Kashmir War with India in 1965. Foreign involvement During the conflict, Nehru wrote two letters on 19 November 1962 to U.S. President Kennedy, asking for 12 squadrons of fighter jets and a modern radar system. These jets were seen as necessary to beef up Indian air strength so that air-to-air combat could be initiated safely from the Indian perspective (bombing troops was seen as unwise for fear of Chinese retaliatory action). Nehru also asked that these aircraft be manned by American pilots until Indian airmen were trained to replace them. These requests were rejected by the Kennedy Administration (which was involved in the Cuban Missile Crisis during most of the Sino-Indian War). The U.S. nonetheless provided non-combat assistance to Indian forces and planned to send the carrier to the Bay of Bengal to support India in case of an air war. As the Sino-Soviet split had already emerged, Moscow, while remaining formally neutral, made a major effort to render military assistance to India, especially with the sale of advanced MiG warplanes. The U.S. and Britain refused to sell these advanced weapons so India turned to the USSR. India and the USSR reached an agreement in August 1962 (before the Cuban Missile Crisis) for the immediate purchase of twelve MiG-21s as well as for Soviet technical assistance in the manufacture of these aircraft in India. According to P.R. Chari, "The intended Indian production of these relatively sophisticated aircraft could only have incensed Peking so soon after the withdrawal of Soviet technicians from China." In 1964 further Indian requests for American jets were rejected. However, Moscow offered loans, low prices and technical help in upgrading India's