The "Agreement on Inspecting Investment of Sino-Kazakhstan Pipeline Construction and "Framework Agreement on Cooperation in oil and Natural Gas were signed by China and Kazakhstan respectively in June 2003 and May 2004, based on which CNPC and Petro Kazakhstan Incorporated signed the "Fundamental Principles on Atasu-Alashankou oil Pipeline Construction" In April 2006, the"General Working Agreement on Natural Gas Line and Related Sales was signed by China and Turkmenistan, followed by a sharing contract signed in July 2007 in Beijing.