The Czech spy agency said it is "obvious" that Russia was behind two recent cyberattack campaigns against the Foreign Ministry and the country's diplomats.
The agency, known as the BIS, said in its annual report on December 3 that the cyberattacks were part of the most serious wave of cyberespionage to target the Czech Republic.
It says 150 e-mail accounts were hacked in an attack by the Russian state that began in early 2016 and was not discovered until 2017.
It also says a separate Russian cyberattack began in December 2016.
The BIS report concludes that the attacks were part of the Turla malware campaign by Russia's FSB intelligence agency and the APT28 or “Fancy Bear” campaign by Russia’s GRU military intelligence agency.
Other European countries have faced similar attacks.
Czech Prime Minister Andrej Babis said his government will discuss the agency's conclusions in January.