"The parties reaffirmed their resolve to make additional efforts to tackle the problems that have amassed," Sergei Prikhodko said after the talks between Dmitry Medvedev and Alexander Lukashenko in the Black Sea resort of Sochi.

He said Medvedev had described the talks as "open and meaningful."

Relations between the former Soviet neighbors, which have been trying for several years to establish a Union State, have been strained over a series economic and political disputes, including Russian energy supplies, a milk export row and Lukashenko′s reluctance to sign a deal to set up a post-Soviet rapid reaction force.

Prikhodko said Belarus wants to resume discussions on its chairmanship in the post-Soviet Collective Security Treaty Organization after consultations with the member countries.

Lukashenko shunned the CSTO session in Moscow in June in protest against Russia′s brief ban on milk supplies from Belarus, calling the move political. Minsk did not take on the chairmanship in the organization in June. Russia is technically the current CSTO chairman.

Prikhodko said the two leaders had a busy timetable for bilateral meetings before the end of this year.

Medvedev and Lukashenko will attend the large-scale West 2009 military drills in Belarus on September 29 and will meet on the sidelines of the EurAsEC economic forum in late November. Prikhodko said the meetings could pave the way for a session of the Union State′s governing body in December.

Prikhodko also said "headway was made" during the talks on a nuclear power plant, the first one to be built in Belarus.

Russia′s state nuclear power equipment and service export monopoly Atomstroyexport said earlier this month that Moscow and Minsk had agreed a draft contract for the 2,000 MW plant, estimated at $4 billion. And Russia earlier promised a loan to Belarus to implement the project.

However, a source close to the Sochi negotiations said the presidents did not raise the most sensitive issues of gas supplies and a Russian stabilization loan to Minsk.

Russia′s Finance Ministry has delayed the disbursement of the final $500 million tranche of the $2 billion loan to support Belarus amid the ongoing global crisis, saying it needs more assessment of the prospects of loan repayment.