MOSCOW, October 25 (RIA Novosti) - Russia is concerned over a lack of progress in negotiations on a new strategic agreement with the European Union, Russian presidential aide Sergei Yastrzhembsky said on Thursday.

Speaking at a briefing in the run-up to an EU-Russia summit in Mafra, Portugal, on Friday, the Kremlin official said Russia was "as concerned over the problem as the Europeans."

The current Russia-EU partnership and cooperation agreement, signed in 1994, expires in December 2007. Negotiations on a new deal have been stalled by Poland, an EU member since 2004, over Russia's ban on Polish meat products, which Moscow said failed to meet sanitary and safety requirements.

Yastrzhembsky said on Wednesday that the agreement would be extended for one more year.

"This way, the lawful foundation of the relations between Russia and the European Union will be preserved, and no legal vacuum will occur," he said.

EU External Relations Commissioner Benita-Ferrero Waldner said earlier that the 27-nation bloc was ready to launch negotiations on the new agreement. But she said the EU had "solidarity" with Poland, and urged the two countries to improve relations.

In an interview with the Nezavisimaya Gazeta newspaper on Tuesday, the Russian ambassador to the EU, Vladimir Chizhov, said: "We have nothing against solidarity unless it is used to bring bilateral relations between individual member countries and Russia to the wider EU platform... and for attempts to 'push' unilateral solutions using EU mechanisms."

Sunday's resounding victory by Poland's liberal Civic Platform party raised hopes among Russian officials that relations between Moscow and Warsaw could improve, and some progress on a Russia-EU partnership deal could now be reached.

Donald Tusk, leader of the winning Civic Platform party, described as a priority moves to improve relations with Russia and the European Union. Tusk, who is expected to become Poland's new prime minister, said he would make his first trips as premier to Brussels, Washington and Moscow.