evidence: Commentary - Beijing is concerned about a possible influx of Islamic radicals and drugs to western China. The character and type of the units stationed at the base is unclear. However, there is no doubt that one of their tasks is to prevent the illegal movement of people between Afghanistan and Xinjiang, China’s autonomous region inhabited by Muslim ethnic minorities. Since the collapse of the USSR, the People’s Republic of China has adopted a strategy of slowly and regularly building influence in the Central Asian region – from an economic presence through a political influence to security co-operation since 1996 as part of the Shanghai Five (which has been known as the Shanghai Cooperation Organisation since 2001). In 2016, China struck a military deal – the Quadrilateral Cooperation and Coordination Mechanism – with Pakistan, Afghanistan and Tajikistan aimed at cooperation in combating terrorism and improving security. As part of the deal, China is building more than ten guardhouses for Tajikistan on its border with Afghanistan in the Pamir Mountains and has undertaken to equip and train a mountain brigade of the Afghan army.