Hackers have warned Ukrainians to "be afraid and expect the worst" after an assault on dozens of government websites.

"Ukrainian!," read a message in Ukrainian, Russian, and Polish on screens of the Ministry of Foreign Affairs, Cabinet of Ministers, and Security and Defense Council.

It's time to be terrified and assume the worst, because all of your personal information is now public. This is for you in the past, present, and future," the hackers declared.

Ukrainian authorities have not revealed who is responsible for the intrusion, although Russian hackers have been implicated in similar attacks in the country in the past.

While the fight over South Ossetia between Moscow and Tbilisi was brief, identical cyber methods were used against Georgian official websites in 2008.

 And in 2015, Sandworm, a Russian hacking group, hit Ukraine's power grid.

According to European Union High Representative Josep Borrell, a coordinated effort to restore computer systems has been mobilised.

There appears to have been no progress this week between Russian envoys and European and NATO leaders in Vienna and Brussels.

During an interview with NPR on Thursday, U.S. Secretary of State Antony Blinken said that the United States was prepared for a Russian invasion of Ukraine and ready to undertake.

Ukrainian government looking for the attackers