Ukraine has been hit by a "massive cyber attack", knocking a number of key government websites offline and issuing a warning to the public to "expect the worst".
The disruption comes at a time of extreme tensions with Russia, which has massed around 100,000 troops at Ukraine's boarder.
Ukrainian cyber police launched an investigation into the attack and have yet to attribute blame.
A spokesman for the Ministry of Foreign Affairs said: "It's too early to draw conclusions, but there is a long record of Russian assaults against Ukraine."
Websites for the foreign ministry, national security and defence council and the government's cabinet of ministers were among those affected.
The foreign ministry spokesman said: "As a result of a massive cyber attack, the websites of the Ministry of Foreign Affairs and a number of other government agencies are temporarily down.
"Our specialists are already working on restoring the work of IT systems, and the cyber police opened an investigation."
The government said the content of the sites had not been changed, and no personal data was leaked.
'We can imagine who is behind it'
It said in a statement that a number of other government websites had been suspended to prevent the attack from spreading to other resources, but most of those affected were quickly restored.
Asked whether Russia was suspected as being behind the attack, the spokesman said: "It's too early to draw conclusions, but there is a long record of Russian assaults against Ukraine."
The EU's foreign policy chief Josep Borrell condemned the attack, saying he "has no evidence who was responsible", but "we can imagine who is behind it".
An emergency EU meeting has been called to respond, he added.
Were any other websites affected?
The education ministry website was also impacted.
By midday Ukrainian time (10am UK) some of the websites were back online though the foreign and education ministry websites still seemed to be down.
"Due to the global attack on the night of Jan. 13-14, 2022, the official website of the Ministry of Education and Science is temporarily down," the ministry said on Facebook.
On some of the websites, a text in three languages - Ukrainian, Polish and Russian - said all data of Ukrainians uploaded to the network had become public.
"Ukrainian! All your personal data was uploaded to the public network. All data on the computer is destroyed, it is impossible to restore it," the message reads.
"All information about you has become public, be afraid and expect the worst. This is for your past, present and future."
Why would Russia be suspected?
Russia has repeatedly been accused of cyber attacks against Ukraine, including far more serious cyber assaults such as targeting critical national infrastructure such as power.
Cyber attacks against websites are a much less sophisticated and less harmful form of attack.
Russian cyber attacks previously accompanied military support to separatists in the east of the country following Moscow's annexation of Crimea.
Western officials have been concerned about possible new cyber attacks as tensions mount over the potential for a new Russian invasion of Ukraine.
The targeting of Ukrainian government websites comes at the end of a week of international diplomacy over Ukraine between Russia, the US, and NATO allies that ended without agreement and with both sides signalling worse hostilities could follow.
Russia said dialogue was continuing but was hitting a dead end as it tried to persuade the West to bar Ukraine from joining NATO and roll back decades of alliance expansion in Europe - demands that the US has called "non-starters".
© Sky News 2022