A Central Asian Union was proposed by Kazakhstan President Nursultan Nazarbayev on April 26, 2007, in order to create an economic and political union similar to that of the EU encompassing the five former Soviet Central Asian republics of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan.
So far the presidents of Kazakhstan and Kyrgyzstan have signed an agreement to create an "International Supreme Council" between the two states. In addition, Kazakhstan, Uzbekistan and Kyrgyzstan have signed a Treaty of Eternal Friendship. Kazakhstan and Uzbekistan have also decided to set up a free trade zone.
Though the proposed union has the support of the presidents of Kazakhstan, Kyrgyzstan and Tajikistan, it was outright rejected by Uzbekistan president Islam Karimov.
Central Asian Union Wikipedia
The proposed Union would primarily deal with interstate border issues, trade, visa regimes, tourism and security. If realized, the CAU would represent a counterbalance to the existing Russian-dominated Collective Security Organization and the Chinese-Russian-led Shanghai Cooperation Organization. In his proposal, the Kazakh President said:
"In the region, we share economic interest, cultural heritage, language, religion, and environmental challenges, and face common external threats. The founding fathers of the European Union could only wish they had so much in common. We should direct our efforts towards closer economic integration, a common market and a single currency."