Chinese official sources regard the document as a legal contract that was mutually welcomed by both governments as well as by the Tibetan people. 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. In reality the Tibetan negotiators faced a tough situation - forbidden by Lhasa to discuss the topic of "Tibetan sovereignty", they nevertheless had to accept the reality on the ground. The Chinese military superiority and the threat of a full-scale invasion forced the Tibetan delegation to give in to the Chinese demands and agree to the final treaty dictated by the PRC - against the will of the Lhasa officials in Tibet proper.