Europe gets 4.9 trillion cubic feet of gas from Russia, and 80 percent of that volume transits through Ukraine. Gazprom Wednesday effectively cut off that supply, leaving Europe scrambling for alternatives.

Brussels in 2008 adopted an energy policy that reduces emissions and consumption while examining ways to diversify its oil and gas sector, putting the Nabucco pipeline at the forefront of the agenda, The Guardian newspaper said.

"Diversification on the terrestrial route for gas is a must for Europe," said Czech Deputy Prime Minister Alexandr Vondra. The Czech Republic currently holds the presidency of the European Union.

Nabucco would circumnavigate Russian and Iranian sectors to bring natural gas from Caspian suppliers to European markets through Turkey.

Observers point out, however, that plans to build the pipeline pre-empted plans to secure supplies for the pipeline. Brussels hailed recent gas discoveries in Turkmenistan, but those reserves may be 20 years from full exploitation.

Reinhard Mitschek, head of the six-nation Nabucco in Vienna, said supplier nations expressed interest in joining the project, though reserves so far meet only half of the total expectations.