Stockholm (AFP) - Russia's pipeline project to pump gas to Germany under the Baltic Sea is a bad deal for Europe that would destabilise Ukraine, US Vice President Joe Biden said Thursday.

"From our perspective, the Nord Stream 2 pipeline is a fundamentally bad deal for Europe," Biden said during a visit to Stockholm where he met with Swedish Prime Minister Stefan Lofven.

"To lock in great reliance on Russia will fundamentally destabilise Ukraine," Biden said, adding: "Europe needs diverse sources of gas."

EU states imported 53 percent of their energy in 2014. A third of gas comes from Russia alone and some newer eastern members are almost entirely reliant on Moscow for energy.

The EU has been seeking to reduce its dependence on Russian gas.

The European Commission, the EU's executive arm, has said the Nord Stream pipeline risks concentrating 80 percent of the EU's Russian gas imports on one route and will now look into whether the project meets European laws.

Biden said the energy market "needs to be open and competitive, and everyone has to play by the rules".

In a thinly-veiled reference to Russia, which has on several occasions cut off gas supplies to Ukraine amid disputes, Biden added: "No country should be able to use energy as a weapon, to coerce policies from other nations."

He noted that all European nations were now able to access US liquified natural gas if they wanted.