Russian Foreign Minister Sergei Lavrov will visit Poland to discuss a controversial US anti-missile defence system, dpa reported, refering to the Interfax news agency.
Russia's top diplomat also was likely in talks with Polish leadership to lay out the Kremlin's position on the South Ossetia war, according to the report.
Poland is one of the most outspoken critics of Russia within the European Union. During a recent EU summit meeting on the Caucasus, Poland and Britain were part of a loud minority calling for immediate sanctions on Russia for its military occupation of Georgian territory.
Relations between Moscow and Warsaw, never good, also are in poor condition because of sharp differences over trade issues, international security, and energy.
Warsaw had long resisted a US plan to emplace portions of an anti-missile system in its territory, but quickly agreed to the programme upon Russia's invasion of Georgia.
The Kremlin has called the system - to be based in both Poland and the Czech Republic - dangerous and threatening to Russia's intercontinental missile force, despite US claims the anti-missile net is aimed at rogue states.