Russia quietly got rid of dozens of buoys in the Narva River that served as border markers with NATO ally Estonia.
Estonia accused Russia of removing 24 of 50 buoys overnight Wednesday which separate the two countries, according to Bloomberg.
The floating markers were placed on the river by Estonian authorities May 13 to help small boats navigate the water without deviating into Russian territory, the country said, according to the outlet.
"This year, Russia announced that they would not agree with the locations of about half of the planned" buoys, Estonia's border guard service said in a statement, The Moscow Times reported.
On Thursday, Estonian "border guards detected that the border guards of the Russian Federation had begun to remove floating markers," the statement continued.
Estonian Prime Minister Kaja Kallas said government officials were investigating the incident, which comes a day after Russia deleted an online draft decree that would've shifted the borders of the Baltic Sea and expanded the country's maritime territory.
Had the Russians moved forward with the drafted boundaries, they would have encroached on territories belonging to Finland and Lithuania.
"Russia uses tools related to the border to create fear and anxiety, with which to sow insecurity in our societies," Kallas said. "We see a broader pattern of this."