Turkmenistan has not dropped plans for a trans-Caspian Sea gas pipeline that would bypass Russia despite agreeing to a rival line along the coastline to Russia.
Turkmen President Kurbanguly Berdymukhamedov said the deal reflected the worldwide trend of diversifying export routes.
His counterparts from Russia and Kazakhstan agreed today to build the new natural gas pipeline around the Caspian Sea, a move that bolsters Russia's dominance over the region's gas exports.
The new pipeline and an accompanying deal to upgrade existing Soviet-era infrastructure deliver a blow to US, European and Chinese hopes of prising the flow of Central Asian gas out of Russian hands.
Although all three former Soviet republics sought to play down the diplomatic implications of the pipeline, it comes at a time of increased Western anxiety about Russia's use of its vast energy resources for political ends.
The agreement was reached at a summit of the three states in the Turkmen Caspian port of Turkmenbashi.
Russian President Vladimir Putin said the deal meant "more supplies of energy resources to Europe and the world's markets".
In its first stage, the pipeline will deliver 10 billion cubic metres (bcm) of gas per year by 2009-2010, Russian Energy Minister Viktor Khristenko told reporters.
Including the infrastructure upgrade, deliveries to the Russian border will rise to 90 bcm.
"Technological, legal and ecological risks are so big that it will be impossible to find an investor unless it is a political investor who does not care how much gas there is to pump through," Mr Khristenko said.
The three states issued joint declarations saying they would sign a treaty by September on building the new pipeline and would work with Uzbekistan to improve existing Soviet-era Central Asia/Centre pipelines.
New gas finds in Turkmenistan and a new Turkmen leader following the death in December of president Saparmurat Niyazov had raised the possibility that the country, the largest gas producer in Central Asia, might seek new export routes.
Mr Berdymukhamedov said Turkmenistan still had a long-term interest in diversifying pipelines and listed possible projects with Iran, China, Afghanistan, India, and the trans-Caspian.
Kazakh President Nursultan Nazarbayev, who this week pledged to keep most of his country's oil flowing through Russian pipelines, said ahead of the signing: "This is a purely pragmatic commercial project ... There is no politics there."