Before sitting down with Russian President Vladimir Putin, Belarusian President Alexander Lukashenko harshly criticized tax changes that left his country of 10 million people paying a higher price for Russian oil and gas.
Putin had countered by saying that despite the changes, Belarus still paid much less than other countries for Russian energy resources.
The Russian leader confirmed at the start of Tuesday's talks that he and Lukashenko would discuss the issue. Lukashenko said he hoped for a quick resolution.
The two met for more than four hours. Their respective media representatives said they agreed to have another meeting in the next week to iron out remaining differences.
Lukashenko has ruled Belarus with an iron hand for nearly a quarter-century, cracking down on dissent and the media. He has relied on loans and cheap energy from Russia to keep a Soviet-style economy afloat.
Despite the close political, economic and military ties between the two ex-Soviet neighbors, Lukashenko has bristled at what he described as Moscow's attempts to subdue Belarus.
Earlier this month, he accused some politicians in Russia of floating the prospect of incorporating Belarus and said he wouldn't let it happen.