 The Central Tibetan Administration which was formed after 1960 and international law expert Eckart Klein consider it invalid and as having been signed under duress.The United States informed the Dalai Lama in 1951 that in order to receive assistance and support from the United States, he must depart from Tibet and publicly disavow "agreements concluded under duress" between the representatives of Tibet and China.The People's Liberation Army crossed the Jinsha River on 6 or 7 October 1950 and defeated the Tibetan army by 19 October.