"We are open to links to other branch lines. We see Nabucco as a backbone and frontrunner. If that can deliver added value, we can take all suppliers on board," Reinhard Mitschek, managing director of Nabucco Gas Pipeline International GmbH told a conference call.

The Nabucco plan intends to bring gas from the Caspian region to an Austrian hub via Turkey and the Balkans.

Partners in Nabucco include Turkey's Botas, Austria's OMV, Germany's RWE, Hungarian MOL, Romania's Transgaz and Bulgarian BEH.