Russian natural gas company Gazprom this week signed a deal with Turkish pipeline company BOTAS to move forward with the South Stream pipeline through its territory. South Stream is one of Gazprom's alternatives to move around geopolitically sensitive territory in Ukraine.
Nabucco, said spokesman Christian Dolezal, is a unique project for Europe that isn't affected by South Stream's development.
"Nabucco has a very strong legal framework with all transit countries and Turkey in form of the Intergovernmental Agreement as a treaty and the bilateral Project Support Agreement, BOTAS is Nabucco shareholder," he told the Trend news agency.
South Stream, he added, presents a route alternative while Nabucco is a new option with a diversified supplier base.
Nabucco has been criticized because of a lack of firm agreements by potential suppliers. It would get some of its gas from Azerbaijan, which is expected to make a decision on projects to deliver gas to Europe early next year.
Officials from Azerbaijan and Turkey signed a memorandum of understanding this week for construction of the Trans-Anatolia pipeline, which Nabucco directors saw as favorable to their plans.