The European Union this week restarted negotiations with Turkmenistan and Azerbaijan on the possibility of an undersea trans-Caspian natural gas pipeline.

A spokeswoman for EU Energy Commissioner Gunther Oettinger said the topic of a pipeline linking Turkmenistan's gas fields with Azerbaijan -- and from there via Georgia and Turkey to Europe -- was among issues discussed at meetings with his Turkmen and Azeri counterparts, Europolitics.com reported.

Oettinger spokeswoman Marlene Holzner said the EU executive, Turkmenistan Energy Minister Myrat Artykow and Azerbaijan Minister for Industry and Energy Natiq Aliyev all agreed Tuesday in Ashgabat the idea was an important part of efforts to reduce Europe's dependence on Russian gas supplies, and thus should be given new impetus.

The idea for a 185-mile undersea gas pipeline linking Turkmenistan and Azerbaijan has been around for years but there has never been a formal agreement on one. The concept is opposed by Russia and Iran, each of whom say the legal status of the Caspian Sea territory is undefined.

The countries also claim they oppose such a pipeline on environmental grounds.

The European Union, however, has remained keenly interested in the project because of Turkmenistan's potential to add much more gas to the planned Southern Corridor that would link Azerbaijan's Shah Deniz II Caspian Sea gas fields to European customers.

Turkmenistan's reserves are estimated to total more than 26,200 billion cubic meters -- six times more than Azerbaijan's -- placing it third in the world on the list of gas-producing countries.

Turkmenistan has said it would provide Europe with up to 40 billion cubic meters of gas annually through a trans-Caspian pipeline. Some 10 billion cubic meters of the total would come from its Malaysian Petronas field in the Caspian while the rest would be piped 620 miles overland from the Galkynysh field in southeastern Turkmenistan, the Trend News Agency said.

The European Union has made no financial commitment to a trans-Caspian project, but last year was told by member states to make sure any agreement would follow European standards on investments and environmental protections.

Europe hopes the project would link up with one of several possible Southern Corridor gas routes from Azerbaijan to Europe, including the Nabucco proposal, which would run through Georgia and Turkey, or the Azerbaijani-Turkish Trans-Anatolian Pipeline, or TANAP, which would parallel Nabucco's proposed route through Turkey.

Holzner told Europolitics.com a revived trans-Caspian push could add weight to the "original" Nabucco proposal, which has since fallen out of the favor with the consortium controlling the Shah Deniz II field. This year they stated a preference for a shortened "Nabucco West," which would leave the Turkish part of the route to TANAP.

She noted, however, that no feasibility study for the TANAP project has been carried out, while Oettinger doesn't seem to have ruled out the possibility that all the projects may be viable at some point.

A Turkmenistan-Azerbaijan connector would provide direct competition to Russia's planned South Stream gas line crossing beneath the Black Sea, and because of that Baku may be unwilling to upset Moscow by fully backing a trans-Caspian project, some analysts say.

Azerbaijan has yet to indicate a willingness to invest in the project, although it has expressed a readiness to provide its own territory, transit opportunities and infrastructure for the project, Trend reported.