The European Union and Russia agreed at ministerial talks in Dublin on Wednesday to step up efforts to resolve their differences over the EU's enlargement into eastern Europe on May 1.

The EU's Irish presidency had been hoping to announce a deal to modify Russia's trade-based Partnership and Cooperation Agreement (PCA), so that it encompasses the 10 mostly former Soviet bloc states about to join the EU.

No such announcement was made after the meeting in Dublin between Russian Foreign Minister Sergei Lavrov and his Irish counterpart Brian Cowen.

However, Cowen said: "We agreed to step up efforts regarding the few outstanding issues in the coming days."

Lavrov said he had raised Russia's concerns over extending the cooperation agreement, but was positive that a deal would be reached before May.

"We are sure that these concerns will be overcome," Lavrov said.

Russia has shown considerable nervousness at the EU's expansion into its former sphere of influence, plunging relations between Brussels and Moscow to their worst level in years.

Russia has been dragging its feet over the modification of the PCA, concerned notably over the resulting loss of preferential trade tariffs it had negotiated with its former Soviet bloc partners.

Moscow has previously said it wanted compensation, and rising tensions over the disagreement saw veiled warnings from the EU of trade reprisals.

The 15-nation EU signed the PCA with Russia in December 1997, setting out the political, economic and trade frameworks of its relationship with the vast country for the next 10 years.

But the accord now needs to be adapted to include, on the EU side, eight former Soviet satellites -- the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia -- plus Cyprus and Malta.

Discussions are to resume between Russia and the European Commission in Brussels on Thursday and Friday, with a view to reaching a formal deal on April 27, when European ministers meet in Luxembourg, according to source close to the commission.

The optimism of a breakthrough deal recently voiced by Ireland, which currently holds the EU's rotating presidency, matches equally hopeful recent comments from Moscow.

On Monday Russian Deputy Foreign Minister Vladimir Chizhov, who is responsible for European affairs, told a press conference in Moscow he hoped to negotiations would be completed "by the end of this week".

The meeting in Dublin had been due to take place in March but was delayed when then-foreign minister Igor Ivanov lost his job as part of a government reshuffle by President Vladimir Putin. Ivanov was replaced by Lavrov.