evidence: The 1959 Tibetan Rebellion and the 14th Dalai Lama's arrival in neighbouring India made the security of Bhutan's border with China a necessity for Bhutan. An estimated 6,000 Tibetans fled to Bhutan and were granted asylum, although Bhutan subsequently closed its border to China, fearing more refugees to come.[5][11] In July 1959, along with the occupation of Tibet, the Chinese People's Liberation Army occupied several Bhutanese exclaves in western Tibet which were under Bhutanese administration for more than 300 years and had been given to Bhutan by Ngawang Namgyal in the 17th century.[8] These included Darchen, Labrang Monastery, Gartok and several smaller monasteries and villages near Mount Kailas.[12][13][14][15] A Chinese map published in 1961 showed China claiming territories in Bhutan, Nepal and the Kingdom of Sikkim (now a state of India).[5] Incursions by Chinese soldiers and Tibetan herdsmen also provoked tensions in Bhutan. Imposing a cross-border trade embargo and closing the border, Bhutan established extensive military ties with India.[5][9]