A senior U.S. energy official called Turkey and Azerbaijan to reach an agreement over gas and transportation prices through a west-bound pipeline that would carry natural gas to Europe, saying the two countries would otherwise risk forcing energy companies to look for alternative routes. "We strongly encourage Turkey and Azerbaijan to agree on pricing terms because the agreement is needed to win the trust of the participating companies in the Nabucco Pipeline project. A failure to find an agreement would lead energy companies to search for different routes," Richard Morningstar, U.S. special representative for Eurasian energy, told a meeting at Brussels-based think-tank, European Policy Center.

The Nabucco project represents a new gas pipeline connecting the Caspian region, the Middle East and Egypt via Turkey, Bulgaria, Romania, Hungary with Austria and further on with the Central and Western European gas markets.

The pipeline length is approximately 3,300 km leading to Baumgarten in Austria, and the pipeline is expected to reduce EU's natural gas dependence on Russia.

Morningstar said Turkmenistan and Iraq could join in as other suppliers besides Azerbaijan but he indicated that the U.S. was against Iran's participation in the Nabucco project.