Estonian border guards said on Thursday that their Russian counterparts had overnight removed buoys from the Narva River, which divides the two neighboring countries, amid a dispute over their shared border.

Tallinn said it was only after the full-scale invasion of Ukraine that Moscow challenged the placement of floating markers used to prevent boats from accidentally entering foreign waters.

“This year, Russia said it would not agree to the location of about half of the planned” buoys, the Estonian border guard said in a statement.

Early on Thursday morning, Estonian “border guards discovered that the border guards of the Russian Federation had begun to remove the floating signs,” the agency added.

Estonian Prime Minister Kaja Kallas told reporters that her government was “examining” the circumstances of the buoy’s removal with authorities in Moscow.

She added that “Russia is using border-related tools to create fear and anxiety with which to spread insecurity in our societies. We see the bigger picture of this.”

The incident came two days after the Russian government published a draft regulation introduced by the Russian Defense Ministry that would seek to redefine the country's maritime borders around the Baltic exclave of Kaliningrad and the eastern Gulf of Finland.

The proposal, which has since been removed from the government website, sparked outrage from Russia's Baltic Sea neighbors, who called it an attempt to sow confusion and destabilize regional security.

While the Kremlin insisted on Wednesday that the draft resolution was not politically motivated, experts believe the proposed changes could be used to put pressure on Russia's Baltic Sea neighbors, all of which are members of the EU and NATO.