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 defence ministry’s work to clarify the border was of a technical nature.
