Earlier in the day, Ukrainian Foreign Ministry spokesman Oleg Nikolenko said the websites of the ministry and some other government agencies were down due to malicious cyber activities. The website of the education ministry displayed a message about an alleged leak of the personal data of Ukrainians onto the internet.
"I strongly condemn the cyber attacks on the Ukrainian Government. NATO has worked closely with Ukraine for years to help boost its cyber defences," Stoltenberg said.
Stoltenberg added that NATO experts in Brussels have been exchanging information on the cyberattacks with their Ukrainian colleagues.
"In the coming days, NATO and Ukraine will sign an agreement on enhanced cyber cooperation, including Ukrainian access to NATO’s malware information sharing platform. NATO’s strong political and practical support for Ukraine will continue," Stoltenberg said.
The Polish Foreign Ministry also condemned the cyberattacks against Ukraine.
"We are concerned about the reported cyber attack on the Ukrainian government websites, including the MFA @MFA_Ukraine. We strongly condemn all actions that result in spreading disinformation and disrupting the functioning of government institutions," ministry spokesman Lukasz Jasina tweeted.
Concerns about the cyberattack on Ukrainian sites were also voiced by White House Press Secretary Jen Psaki, who noted that President Joe Biden has been briefed on the incident.
"We are also in touch with Ukrainians and have offered our support as Ukraine investigates the impact and nature and recovers from the incident," Psaki told reporters.
The US does not have attribution at this time, Psaki also said, adding that the US will continue to work with Ukraine to assess any additional impacts.
The Ukrainian State Service of Special Communication and Information Protection said later that most of the websites had been restored and personal information not disseminated. The service called the attack the worst in the past four years.