TEHRAN, January 22 (RIA Novosti) - Iran could contribute natural gas to the planned Nabucco pipeline to pump Caspian gas to Europe via Turkey, bypassing Russia, the Islamic Republic's foreign minister said on Tuesday.

Speaking in Bulgaria, Manouchehr Mottaki said, as quoted by Iranian media: "The European Union has stated a need to diversify sources and routes of natural gas supplies. Nabucco is one of the possible projects of cooperation between Iran and the EU in the energy sphere."

The $6 billion pipeline, backed by the EU and the U.S. and designed to be laid down via Turkey, Bulgaria, Romania, Hungary and Austria, is a rival project to the South Stream gas pipeline to run from Russia's Black Sea to Bulgaria and further branch off to different destinations in Europe, supplying it with 30 billion cu m of gas annually.

Construction on the Nabucco pipeline is scheduled to begin in 2009, enabling the pipeline to go on stream in 2012.

Russia and Bulgaria signed a $15 billion deal on Friday under which they will hold a 50% stake each in a joint venture to operate the South Stream pipeline across the Balkan state.

Iran's ex-president Ali Akbar Hashemi-Rafsanjani, who is part of the delegation led by Mottaki on the visit to Bulgaria, singled out earlier on Tuesday Bulgaria as a potential energy partner for Tehran.

"Bulgaria is a gateway to Europe, and it could have an important role in economic cooperation with Iran, especially in the oil and gas sector," he said.

Mottaki and his delegation are also expected to visit Portugal and attend the World Economic Forum in Switzerland's Davos on January 23-27.