Russian Finance Minister Alexei Kudrin warned Minsk that media repression from the former Soviet republic would be met with financial consequences.
"We preserve the right to limit financial support to Belarus," he was quoted by Russia's state-run news agency RIA Novosti as saying.
Police blocked off parts of Minsk following cries for mass demonstrations against the economic situation in the country. Bloomberg News reports that inflation in Belarus rose more than 13 percent in May.
Belarusian President Alexander Lukashenka, dubbed the last European dictator by Washington, warned this week he wouldn't tolerate protests over the economy.
The post-election period that brought another term for Lukashenko, the first and only president of an independent Belarus, was marred by widespread unrest that saw six presidential candidates and at least 600 anti-government protesters detained.
Washington and the European Union have slapped economic sanctions on Minsk as a result of the repression.