Companies involved in the construction of Nabucco project started negotiations with German energy group RWE, which has shown interest to take part in the project, Bulgarian sources told Dnevnik newspaper on Thursday.

The five companies involved in Nabucco are Bulgargaz (Bulgaria), OMV(Austria), MOL (Hungary), Botas (Turkey) and Transgaz (Romania).

Bulgargaz representatives confirmed that negotiations had started with RWE which would contribute to the project with an equal quota as the other companies.

However, the first option was Gas de France, which was not agreed by the Turkish side.

The Nabucco pipeline would measure 3300 km in length and costs will amount to 4.5 billion euro. It is due to transport natural gas from the Caspian region and Iran up to Austria.

The first part of the project, 2000 km in length from Ankara, Turkey to Baumgarten, Austria would transport 8 billion sq. meters of gas annually, starting with 2012.

The European Union considers the Nabucco project as essential for assuring energy independence since the project is an alternative to Russian imports.