XI'AN, March 30 (Xinhua) -- China and five Central Asian countries, namely Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan, held a ceremony in the city of Xi'an in Shaanxi province and launched the secretariat of the China-Central Asian cooperation mechanism on Saturday.They hoped that the establishment of the secretariat will inject new momentum into the cooperation between Central Asian countries and China.