The Baltic countries "took advantage of the opportunity offered by the Vienna Document on Confidence- and Security-Building Measures (Chapter III: Risk Reduction) of the Organization for Security and Cooperation in Europe to activate the Mechanism for Consultation and Cooperation as regards unusual Military Activities", the ministry said in a press release.
"The Baltic states have submitted questions to Belarus about the unusual troop build-up for exercises in the territory of Belarus, the military equipment used, the number of Russian and Belarusian soldiers participating, and the planned return to their usual deployment location", it said.
The questions were sent on February 9 and "Belarus is obliged to provide answers by February 11".
"We urge Belarus to respect its international commitments and to provide information on the nature and scale of the military drills," Lithuanian Foreign Minister Gabrielius Landsbergis said in the press release.
"The avoidance to transparently provide information on the military exercises and the deployment of Russian troops in Belarus in line with the international commitments causes serious concerns over aggressive intentions of Russia and Belarus," he said.
The risk reduction mechanism of the OSCE Vienna Document is designed to ensure consultation and cooperation among countries to reduce military risks, ensure transparency and prevent military incidents.
Russia and Belarus on Thursday launched the active phase of a joint military exercise.
Russia's Defense Ministry has said in a press release that the objective of the maneuvers, set to run until February 20, is to "work out the tasks of suppressing and repelling external aggression during a defensive operation".
Moscow and Minsk have not disclosed how many troops are participating in the drills, but the United States has said Russia has sent some 30,000 troops to several regions of Belarus.
Western countries say Russia has amassed a total of over 100,000 troops along Ukraine's borders in what could be preparations for a potential invasion.