A planned press conference was canceled, but media reports say the presidents discussed use of the region's water and energy resources.
The four leaders agreed to revive the Aral Foundation, which the Central Asian states created in the mid-1990s to stem the desiccation of the Aral Sea, which has increasingly caused health problems in the region.
The four later toured Astana, which became the capital of Kazakhstan in 1997, with President Nursultan Nazarbaev showing them the many new buildings in the city.
Uzbek President Islam Karimov congratulated Nazarbaev, saying Astana is an example of "making from nothing a city that can claim to be an absolutely unique place."
An Increasingly Thirsty World
An Iraqi boy drinks from a waste-water reservoir near Baghdad (epa file photo)
A MATTER OF LIFE AND DEATH. Disputes about access to water are increasingly coming to the center of global attention, especially in China, India, and Central Asia. Writing about the 1967 Six Day War in his 2001 memoirs, Israeli Prime Minister Ariel Sharon said that "while border disputes between Syria and ourselves were of great significance, the matter of water diversion was a stark issue of life and death." (more)