In an interview with LRT, Palauskas was asked to comment on a statement in a recent national security report claiming that "there are signs that Russia's special military units are conducting peacetime penetrations into foreign states".

"This is all they said to the Committee [of National Security and Defence] - that there is some likelihood that it has happened. How high is the likelihood is hard to tell, because the evidence has not been verified 100%," Paulauskas said.

He added that the Russian forces could have landed in Juodkrantė, a village on the Lithuanian part of the Curonian Spit, during military exercise.

Asked for comment, Prime Minister Algirdas Butkevičius said on Thursday morning: "I can't [tell you]. This is secret information. The services responded promptly and adequately."

The Curonian Spit is a strip of land in the Baltic Sea. The northern stretch of the strip is Lithuanian territory, while the south is part of the Russian exclave of Kaliningrad, where Russia has been conducting intensive military exercises in recent year.

National Defence Minister Juozas Olekas would not give more details either.

He only said that "all information that we have and can make public is provided in the report of the Second Investigation Department (under the Defence Ministry)".

Conservative MP Rasa Juknevičienė, a former defence minister and now a member of the National Security and Defence Committee, told reporters on Thursday that based on information available to her, no violation of the state border had been registered.