The Nabucco pipeline could be supplied with natural gas by sources in Azerbaijan, Turkmenistan and Iran, but no binding documents have been signed yet. The Bulgarian government has approved an agreement supporting the Nabucco gas pipeline project, the government said in a statement.

The agreement was signed with the project operator, Nabucco Gas International Gmbh.

Bulgaria, Austria, Hungary, Romania and Turkey signed an intergovernmental agreement on Nabucco in Turkey on July 13, 2009. Bulgaria's parliament ratified the agreement in February.

That agreement calls for the participants to conclude bilateral agreements with Nabucco Gas International in order to facilitate project financing and implementation.

It was reported earlier that Russia and Bulgaria signed the road map on construction of another gas pipeline, South Stream, last weekend. In exchange, Bulgaria secured a preferential price for Russian gas and removal of intermediaries from the supply chain.

Nabucco will have capacity to deliver 31 bcm of gas from the Caspian region to Europe, bypassing Russia. The Nabucco consortium includes German RWE, Austrian OMV, Turkish Botas, Romanian Transgaz, Bulgarian Bulgargaz and Hungarian MOL.

So far it is not clear where Nabucco will get its gas supplies. The sources being considered are Azerbaijan, Turkmenistan and Iran, but no binding documents have been signed with them.

South Stream will cross under the Black Sea from Russia to countries in Southern and Central Europe.

The undersea section of the pipeline will come ashore on Bulgaria's coast (although Gazprom recently examined options to lay the pipeline through Romania). South Stream will have capacity to ship 63 bcm a year.

Intergovernmental agreements on construction of the onshore segment of the pipeline have been signed with Bulgaria, Serbia, Hungary, Greece, Slovenia, Croatia, and Austria.