France's GDF Suez said Tuesday that it agreed to buy from Austria's OMV a nine-percent stake in the planned Nabucco West gas pipeline.
OMV said this was a "clear sign of the broad pan-European backing for the project," which also involves Bulgaria's BEH, Turkey's BOTAS, Hungary's Transgaz.
GDF Suez said the deal, financial details of which were not disclosed, "re-asserts its position as a key player in European natural gas."
Initially the Nabucco project aimed to transport some 30 billion cubic metres of gas per year from the Caspian Sea to Europe.
It is one of two proposed pipeline to bring gas from a huge new Caspian Sea gas field in Azerbaijan being developed by the Shah Deniz consortium.
Originally planned to run through Turkey to Austria via Hungary, Romania and Bulgaria, the 3,900-kilometre (2,400-mile) pipeline has been plagued by problems, including a lack of potential suppliers, that have repeatedly delayed the start of construction.
In a bid to breathe life back into the project, its shareholders have proposed a shorter, less costly pipeline, Nabucco West, which will transport 10-23 billion cubic metres of gas from the Bulgarian-Turkish border to Austria.
Last month Germany's RWE sold a 17-percent stake in Nabucco to OMV.