Russia may hold military exercises to put pressure on Lithuania after the country enforced EU rules stopping the rail transit of sanctioned goods to Kaliningrad, director of the International Center for Defense Studies (ICDS) Indrek Kannik said.
Russia has said Lithuania will face consequences for its actions, asked what may be done in retaliation, Kannik said one option could be military exercises on the country's borders.
"The most realistic is military exercises either in the Baltic Sea or on Russian and Belarusian territory near the Lithuanian border," he said.
"The next step would already be military aggression, but I do not believe that because Russia does not have has the strength to start a war against NATO."
On June 17, EU sanctions forbidding the transport of items such as building materials, metals, cement and steel to Russia kicked in.
In Lithuania's case, this means sanctioned items can no longer be transported to Kaliningrad by train across Lithuania. Passengers can still take the train to the region and non-sanctioned goods can be delivered.
Russia, which is also still able to make deliveries to the exclave by air and ship, has threatened to retaliate against Lithuania calling the move a "blockade", which Lithuania Prime Minister Ingrida Šimonyte denies.
The EU has confirmed the country is enforcing collective sanctions and not acting "unilaterally" as Russia says.
Estonia has said it stands in solidarity with Lithuania and told Russia's ambassador to Estonia that it must stop threatening its neighbors.
Russian threat to Estonia reduced for near future
Asked whether the military threat to Estonia had increased or decreased since Russia launched its full-scale war on Ukraine on February 24, Kannik said it has reduced.
"In the short term, it has decreased as most of the Russian units are at war in Ukraine and most of the units [usually stationed] on our border are also at war in Ukraine," he said.
"But in the long run, it is clear that if Russia were to achieve its military goals in Ukraine, which I do not see at the moment, then, of course, the risk would increase. Russia would not stop there if it succeeds in Ukraine," Kannik said.
The head of ICDS was not concerned about Russia violating Estonia's airspace with a helicopter on Saturday. He said similar actions happen several times a year.
Editor: Helen Wright