Thousands of people took to the streets in Moldova's capital, Chisinau, on Sunday to protest high energy prices.
Local media say the demonstration was called for by the country's pro-Russian opposition.
Participants reportedly urged the government to cover gas and electricity bills for the three-month period from last December to February.
An image shows protestors holding national flags of Moldova and calling for the resignation of President Maia Sandu and other administration officials.
Local media say authorities detained more than 50 people for allegedly carrying knives or other prohibited items and for other reasons.
Moldova's government does not control the pro-Russian breakaway region of Transdniestria in the country's east. Moscow stations its troops and wields strong influence in the area.
Since Russia invaded Moldova's neighbor, Ukraine, the pro-Western governments in Chisinau and Kyiv have been on heightened alert against the Russian military's possible intervention in Transdniestria.