Russian border guards have removed navigation buoys from the Estonian side of a river separating the two countries, the Baltic nation said on Thursday, adding that it would seek an explanation as well as a return of the equipment.
Some 24 out of 50 buoys recently placed on the Narva river to mark sailing routes were removed in the early hours of Thursday the Estonian police and border guard said in a statement.
Natural changes to the riverbed make it necessary to retrace shipping routes annually, the authority said, adding that the location of buoys between Russia and Estonia had been disputed since the Russian full-scale invasion of Ukraine in 2022.
The Russian defense ministry earlier this week briefly published a proposal to revise Russia's maritime border in the eastern Baltic Sea, but later deleted it from an official portal after creating concern among NATO members, including Estonia.
It was not immediately clear if the removal of buoys was related to any Russian Baltic Sea border plan.
"We will approach this case in a sober, balanced way, engaging with allies where necessary," Estonian Prime Minister Kaja Kallas told a weekly government press conference on Thursday, public broadcaster ERR reported.
"We see a broader pattern of Russian actions trying to sow anxiety," she added.
The Narva river runs from a lake between Russia and Estonia and ends up in the Gulf of Finland, part of the Baltic Sea.
The Russian Foreign Ministry did not immediately respond to a request for comment.
Russian Foreign Ministry spokeswoman Maria Zakharova said on Thursday that Russia's Baltic Sea borders should be in accordance with international law, and that the defense ministry's work to clarify the border was of a technical nature.
(Reuters - Reporting by Andrius Sytas, writing by Louise Rasmussen, editing by Terje Solsvik and Philippa Fletcher)