Lithuania still has some reservations regarding the launch of a new European Union partnership agreement with Russia ahead of an officials' meeting in Brussels, according to dpa. "There are a few buts remaining to be solved, but I hope the new mandate will be approved at the meeting," Lithuanian Foreign Minister Petras Vaitiekunas told reporters Tuesday in the Latvian capital, Riga. Vilnius has threatened to formally block an EU agreement to start strategic partnership talks with Russia in protest at Moscow's closure - allegedly for technical reasons - of the pipeline feeding Russian oil to Lithuania's only oil refinery. The EU foreign ministers are due to discuss starting talks on the new EU-Russia partnership agreement in Brussels on Monday, which requires the agreement of all 27 EU members. Vaitekunas spoke after a meeting in Riga with Latvian Foreign Minister Maris Riekstins, Estonian Foreign Minister Urmas Paet, and German Foreign Minister Frank-Walter Steinmeier. Germany's Steinmeier, however, was optimistic about the new mandate. He told reporters Tuesday he was confident the new EU-Russia partnership agreement can be reached in Brussels on Monday. Lithuania agreed to lift its veto on the launch of the partnership agreement with Russia on May 11. At that time, Lithuania negotiated the deal with three EU foreign ministers: Sweden's Carl Bildt, Poland's Radoslaw Sikorski and Slovenia's Dimitrij Rupel, whose country chairs the EU presidency until June. Breaking away from the Soviet Union in 1991 and joining the EU in 2004, Lithuania wanted to see a declaration on legal cooperation in the mandate, urging Russia to help investigate who was behind sending Soviet tanks to the Baltic nation in January 1991, killing 14 people and injuring 700 others. Saying that Russia's actions in the so-called "frozen conflicts" are connected with the security of Lithuania and, in turn, the EU, Lithuania wanted to add a declaration regarding Georgia and Moldova in its negotiating mandate. The former Soviet republic of Georgia is going through a bitter dispute with Russia over the breakaway Georgian regions of South Ossetia and Abkhazia, run by pro-Moscow separatists in the presence of Russian troops. The mandate will be discussed at a Tuesday meeting of the council of foreign ministers from the 27-nation EU, which will have to approve Sunday's deal before Lithuania formally lifts its veto. Any EU member can block talks between the union and other countries if it feels its national interests are being sidelined as Poland did in 2006.