The European Union has condemned Russia for removing buoys on the Narva River at the border with Estonia.
Estonian officials said a total of 24 of the 50 buoys marking navigation routes were removed early Thursday morning.
Border tensions have increased since Russia launched a full-scale invasion of Ukraine in 2022.
EU foreign policy chief Josep Borrell said “such behavior is unacceptable.”
“This border incident is part of Russia’s wider provocations and hybrid operations, including at its maritime and land borders in the Baltic Sea region,” he said in a statement.
Estonia’s border guard said Moscow took issue with the placement of floating markers used to prevent ships from straying into foreign waters, and took issue with the planned locations of about half of the 250 buoys.
Estonian Prime Minister Kaya Karas said she was trying to clarify the situation with Russia.
She said it appeared to be part of a “wider pattern of actions” by Moscow using “border-related tools to create fear and anxiety.”
Estonia’s Foreign Ministry said it had summoned the Russian charge d’affaires and regarded the move as a “provocative border incident.”
It said in a statement that it had requested the “immediate return” of the buoy.
It comes after the Russian Defense Ministry briefly released proposals this week to revise its maritime borders in the Baltic Sea.
The proposal was removed after raising concerns among NATO members, including Estonia.
Moscow has yet to comment.