He said this in a post on X, Ukrinform reports.
"Recent Russian provocations at EU and NATO borders in Estonia, Finland, and Lithuania are part of Russia's typical hybrid tactics of bullying and intimidation. Ukraine has seen such Russian actions many times before. We know that the most effective way to counter them is through unity, strength, and unwavering mutual support," Kuleba said.
According to him, Ukraine expresses its "full solidarity with our Estonian, Finnish and Lithuanian friends."
"We remain vigilant and prepared to provide any necessary assistance in countering Russia's hybrid threats. We also call on NATO to act resolutely in protecting Estonia, Finland, and Lithuania. When we all stand strong and united, no one will be able to intimidate us," Kuleba wrote.
Russian border guards removed more than 20 buoys demarcating shipping lanes from the Narva River on May 23, Estonia's Police and Border Guard Board (PPA) said. Estonian Foreign Minister Margus Tsahkna said that he would summon Russia's charge d'affaires ad interim.
The border between Russia and Estonia stretches for more than 300 kilometers, partly along the Narva River and Lake Peipus.