Announcement came the same day the United States released intelligence findings suggesting Russia is planning a sabotage operation to create a pretext to invade Ukraine.
NATO announced it planned to deepen cyber cooperation with Ukraine after a sweeping attack knocked out key government websites in Kiev at a time of mounting tensions between Russia and the West over Ukrainian security.
"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," Secretary General Jens Stoltenberg said Friday.
The European Union was also mobilising to aid its close ally after the attacks temporarily brought down sites, including those of the foreign ministry and cabinet.
Kiev said the damage was limited and held back on apportioning blame but the ex-Soviet country has accused Russians with links to Moscow for previous hits on websites and key infrastructure.
Russia behind attack?
Without naming Moscow, aide to Ukraine's President Volodymyr Zelenskyy, Andriy Yermak, said Western and Ukrainian intelligence believed the cyberattacks were part of a plot for the "destabilisation of the situation in Ukraine".
Ukraine's foreign ministry described the attack that brought down its site and other government portals as "massive".
The targeted sites, including the emergencies ministry, education ministry and cabinet, displayed a message in Ukrainian, Russian and Polish warning Ukrainians that their personal data had been compromised.
"All information about you has become public, be afraid and expect the worst," the message read.
Within hours of the breach early Friday the SBU security services said access to most hit sites had been restored and that the fallout was minimal.
"The content of sites has not been changed and according to preliminary information no personal data was leaked," the SBU security service said in a statement.
Later Friday it had uncovered clues Russia could have been behind a cyber attack that knocked out government websites in Kiev at a time of mounting tensions between both neighbours.
The "investigation is still ongoing but the security service of Ukraine has obtained preliminary indicators suggesting that hacker groups associated with the Russian secret services may stand behind today's massive cyberattack on government websites", foreign ministry spokesman Oleg Nikolenko said on Twitter.
Russian military drills
Kiev did not immediately blame any individual or entities and the EU's foreign policy chief Josep Borrell said it was too early "to point the finger at anybody. We don't have proof".
But he added: "You can imagine who did this."
In October 2020, the United States charged six Russians with carrying out cyberattacks on Ukraine's power grid, the 2017 French elections and the 2018 Winter Olympics.
The Justice Department at the time said the six were current or former members of the GRU Russian military intelligence and were also accused of staging a malware attack called "NotPetya" that infected computers of businesses worldwide causing nearly $1 billion in losses.
The latest attack came at a time of high-voltage tensions between Russia and the West over Ukraine, a close ally of the United States and Europe.
Those ties deepened after Russia in 2014 annexed the Crimean peninsula from Ukraine and threw it weight behind pro-Moscow separatists that control sections of the east of the country.
The West has accused Russia of deploying tanks, artillery and about 100,000 soldiers on Ukraine's war-torn eastern border in recent weeks, in what NATO says is preparation for an invasion.
The US ambassador to NATO, Julianne Smith told reporters in Brussels that "we all understand there is an array of scenarios that could unfold as it relates to what's happening between Russia and Ukraine".
"And one is a full scale conventional military attack, and there are other layers to it and we'll have to see what we find out today," she said.
Moscow says it has no plans to invade Ukraine.
However, an anonymous US official said Friday that Moscow had put in place operatives trained in explosives to carry out a "false-flag" operation in eastern Ukraine that would create a pretext for an invasion.
Kremlin spokesman Dmitry Peskov dismissed the reports as "unfounded".
Footage published by the Russian defence ministry Friday showed Russian tanks and infantry carrying out firing drills near the city of Rostov-on-Don in southern Russia near Ukraine.
Moscow says this is a response to what it sees as the growing presence of NATO in its sphere of influence, where it fiercely opposes the expansion of the Atlantic alliance.
Russia also says the US-led military alliance should not admit Ukraine or Georgia as new members.
This week the United States and its NATO allies held talks with Russia in an attempt to ease tensions, but all three rounds of negotiations -- in Geneva, Brussels and Vienna -- proved unsuccessful.
Latin America deployment
Deputy Foreign Minister Sergei Ryabkov said Thursday that Moscow saw no reason to hold a new round of security talks with the West following a lack of progress.
Ryabkov also said he did not rule out the possibility that Moscow could deploy forces to allies Venezuela or Cuba if diplomacy failed.
Ukraine on Friday proposed three-way talks with US President Joe Biden and Russian President Vladimir Putin amid fears of invasion.
"We are still waiting for the reaction on this, I think, from the Russian side. But our American partners take our proposal with some interest," Yermak told the Atlantic Council think-tank in Washington.