LUXEMBOURG, April 29 (Xinhua) -- The European Union (EU) failed on Tuesday to start talks with Russia on a key partnership treaty as Lithuania refused to approve the launch due to bilateral disputes with Moscow.

    "We have not completely finished our consultations in the EU regarding the PCA (Partnership and Cooperation Agreement), but it will be ready in a couple of weeks," said Slovenian Foreign Minister Dimitrij Rupel, whose country holds the rotating EU presidency.

    "It (PCA) will be the cornerstone of our relations," Rupel told reporters after a EU-Russia ministerial troika meeting in Luxembourg.

    EU foreign ministers, who met in Luxembourg Tuesday, have been trying to adopt a negotiating mandate so that the European Commission can start talks with Russia on the wide-ranging pact, which will cover issues from energy and security policy to justice and scientific research.

    The previous PCA treaty was signed in 1997 and expired last year. The EU failed last year to start talks with Russia on a new pact due to opposition from Poland which was angry at a meat embargo by Moscow in 2005.

    EU officials did not elaborate on the failure to reach an agreement, but Luxembourg's Foreign Minister Jean Asselborn said earlier Tuesday that it was Lithuania which blocked the start of EU-Russia talks.

    Vilnius has been annoyed by the disruption in July 2006 of Russian oil supplies to Lithuania via the Druzhba pipeline, and the 1991 killing of seven Lithuanian border guards at the country's Medininkai border post by Soviet special forces.

    Lithuania indicated that the provisions of an energy charter should be obligatory and that the Medininkai incident be mentioned in the declaration.

    EU officials said Tuesday they are preparing for the EU-Russia summit in Khanty-Mansiysk, Russia on June 26-27, when the two sides will discuss deepening bilateral cooperation.