Uzbekistan is also a member of the Shanghai Cooperation Organisation (SCO) and hosts the SCO's Regional Anti-Terrorist Structure (RATS) in Tashkent. Uzbekistan joined the new Central Asian Cooperation Organisation (CACO) in 2002. The CACO consists of Uzbekistan, Tajikistan, Kazakhstan, and Kyrgyzstan. It is a founding member of, and remains involved in, the Central Asian Union, formed with Kazakhstan and Kyrgyzstan, and joined in March 1998 by Tajikistan.