"We take it seriously. All other threats from the Belarusian regime after the migrant crisis have already shown that they should be taken seriously because they can become a reality," he told reporters.
Belarusian Prime Minister Roman Golovchenko said on Tuesday that Minsk would take tough retaliatory measures after Vilnius halted the transit of Belaruskali potash fertilizers via Lithuania.
According to Golovchenko, Minsk's measures will be targeted at trains coming from Lithuanian territory.
However, Landsbergis said that no concrete action had been taken on this yet, adding that it was too early to speak about Lithuania's possible response.
"It is too early to say," he said. "We are looking at the situation."
Lietuvos Gelezinkeliai (Lithuanian Railways, LTG) has terminated its long-term contract with the US-sanctioned Belarusian potash giant as of February 1 after the Lithuanian government ruled on January 12 that it was not in line with national security interests.
LTG told BNS on Wednesday that it had no official information from Belarus about any blocking of trains.
Not including empty potash fertilizer wagons that are still returning to Belarus after being unloaded in Klaipeda, around 18 trains should be travelling from Lithuania to Belarus per day on average, according to the state-owned railway company.
"In February, trains loaded at Lithuanian stations should make up about 30 percent of all trains crossing the Lithuanian-Belarusian border from the Lithuanian side daily, with most of them going to Belarus, Russia and Ukraine," it told BNS in a comment.
According to LTG, trains formed in Lithuania mainly carry oil products, fertilizers and ferrous metals.
In response to the halt of the transit of Belaruskali fertilizers via Lithuania, Belarus' authoritarian President Alexander Lukashenko said last week that the Minsk regime might block the flow of Lithuanian goods through the country.
He said Belarus might redirect its export flows from Baltic ports to Russian ports.
The US imposed sanctions on Belaruskali, one of the world's biggest potash producers, last August. The sanctions came into force in early December.