Lithuanian authorities are on high alert for cyber attacks after a massive data leak involving more than 600,000 entries from national data registers, which the government says is believed to be the work of another country.The Lithuanian general prosecutor’s office on Friday announced the leak was primarily from registers of real estate and legal entities accessed by using login credentials of institutions authorised to receive the data.The head of the State Enterprise Centre of Registers, Adrijus Jusas, resigned on Monday following the leak.The authorities immediately implemented additional cybersecurity measures, including blocking the accounts of suspected data users and restricting access with a requirement to update credentials, the prosecutors said.The prosecutor’s office said a foreign country is suspected of involvement. While authorities did not specify which nation they suspect, opposition politician Laurynas Kasčiūnas wrote on social media on Sunday that the data theft is thought to be a Russian intelligence operation. He offered no evidence for the claim.Kasčiūnas warned that addresses of intelligence officers, military personnel, diplomats or politicians may have been accessed, which could potentially allow the perpetrators to spy on or exercise pressure against the targets.Lithuanians are especially cautious given that the country is one of the main targets of Russia’s hybrid war against Europe, which includes sabotage, arson attacks and vandalism, as well as influence operations and attacks on digital infrastructure and government systems.The country has also lately faced a rash of drone sightings over its territory. Last Wednesday, residents of the capital, Vilnius, were told to take cover due to drone activity near the border with Belarus.Speaking to Euronews after the incident, Lithuanian Defence Minister Robertas Kaunas warned that “this is the new reality of what the Baltic states face”.“We need to adapt because the possibility of repeated similar scenarios is very high,” he said.European Commission President Ursula von der Leyen is travelling to Vilnius tomorrow to meet Baltic leaders for talks on coordinating a response to the apparently escalating drone incursions.