Turkmenistan has pledged to supply natural gas for the planned Nabucco pipeline - a major project that should allow EU countries to rely less on Russian energy in future.
Turkmenistan says it will have up to 40bn cubic metres (1,412bn cu ft) of spare gas annually, "so European countries need not worry".
The pledge came from Turkmen Deputy PM Baymyrad Hojamuhamedov on Friday.
Uncertainty about Nabucco's gas supply has been delaying the project.
The 3,300km (2,046-mile) pipeline is expected to pump up to 31bn cubic metres of gas annually from the Caspian region and Middle East across Turkey and into Europe.
In July 2009 Turkey, Romania, Bulgaria, Hungary and Austria signed an agreement to build the long-planned pipeline.
Turkmenistan's announcement came at an international energy conference in the ex-Soviet republic's capital, Ashgabat.
New export markets
Mr Hojamuhamedov said Turkmenistan had support from its Caspian neighbours for building a pipeline under the Caspian Sea, to connect up to the Nabucco pipeline.
He said delivering gas to Europe was part of Turkmenistan's plan to diversify its export markets. It already sells gas to Iran, China and Russia.
Nabucco is expected to cost about 7.9bn euros (£6.7bn) and is projected to come on stream by the end of 2014, Reuters news agency reports.
Russia is forging ahead with South Stream, a pipeline that will run from southern Russia under the Black Sea to Bulgaria. It is seen as a major rival to Nabucco.
The EU relies on Russia for a quarter of its total gas supplies. Seven countries in the 27-nation bloc are almost totally dependent on Russian gas.