Kazakh President Nursultan Nazarbayev said his nation was eager to develop cooperation in the "transit of hydrocarbons not only through the existing northern route, but also other transport routes to the east, west and south."

Russia, the United States, China and other nations have been jockeying to control vast energy resources in Central Asia and the Caspian Sea region -- the rivalry widely compared to the 19th century's Great Game for dominance in the region between the British and czarist Russia.

The Kremlin scored a victory in May by securing a landmark deal to build a pipeline along the Caspian Sea coast to ship Turkmen natural gas to Western markets via Kazakhstan and Russia.

The deal was a blow to U.S. and European efforts to secure alternatives to Middle Eastern oil and gas that would be independent from Russian influence.

However, both Nazarbayev and Turkmen President Gurbanguli Berdymukhamedov have appeared eager to develop alternate export routes under the Caspian to Azerbaijan and to Western markets. They also have been keen to explore potential routes to China, which has shown an increasing appetite for energy.

"One route is from Turkmenistan via Kazkhstan to Russia," Nazarbayev said Tuesday. "Another route is to China, a third route is via Iran to the Persian Gulf. And we don't exclude using the Caspian as a transport corridor."

Berdymukhamedov, elected earlier this year to succeed longtime autocratic ruler Saparmurad Niyazov, who died in December, invited Kazakh companies to help tap Turkmenistan's rich offshore energy riches.

Berdymukhamedov has signed deals allowing companies from Russia, China and the Middle East to search for and develop oil and gas on Turkmenistan's Caspian shelf and in the deserts that cover most of the country.

The country is the second-biggest gas producer in the former Soviet Union after Russia.

Turkmenistan extracts about 2.5 trillion cubic feet of gas annually and Russian state-controlled gas giant OAO Gazprom currently controls the only transit route for exports to other ex-Soviet republics and Europe.

The landlocked Caspian Sea is believed to contain the world's third-largest energy reserves. Turkmenistan shares rights to the sea floor with Azerbaijan, Iran, Kazakhstan and Russia. The nations have failed to agree on the boundaries of their respective sectors.