The United States believes Russia is laying the groundwork for a possible invasion of Ukraine and could stage a "false-flag" attack in the militant-held east of the country to justify a major assault in the coming weeks.
Washington issued the warning as Ukraine’s government worked to restore the websites of dozens of ministries and state agencies, which were brought down by a cyberattack in the early hours of Friday by hackers who left an on-screen warning telling the country to “be afraid and expect worse”.
In three high-level meetings this week, western officials rejected Russia's demand that Nato bar the admission of any more countries in eastern Europe and withdraw troops and military hardware from the region.
Moscow has vowed to respond with “military-technical” measures if its security demands are not met, and is continuing to send soldiers and armour to areas near Ukraine where it has now amassed an estimated 100,000 troops.
"As part of its plans, Russia is laying the groundwork to have the option of fabricating a pretext for invasion, including through sabotage activities and information operations, by accusing Ukraine of preparing an imminent attack against Russian forces in eastern Ukraine," White House spokeswoman Jen Psaki said on Friday.
Russia “plans to begin these activities several weeks before a military invasion, which could begin between mid-January and mid-February,” she said.
“We have information that indicates Russia has already prepositioned a group of operatives to conduct a false-flag operation in eastern Ukraine. The operatives are trained in urban warfare and in using explosives to carry out acts of sabotage against Russia’s own proxy forces.”
Moscow insists it is not planning an all-out invasion of Ukraine, where in 2014 it annexed Crimea and fomented a war in the eastern Donbas region that has now killed more than 14,000 people.
"We're waiting for written responses from our colleagues" in the US administration and Nato, Russian foreign minister Sergei Lavrov said on Friday on the results of this week's talks.
“We have run out of patience ... The West has been driven by hubris and has exacerbated tensions in violation of its obligations and common sense,” he complained, adding that Russia’s security demands were “a package, not a menu” from which the US and its allies could pick and choose.
“They must understand that the key to everything is the guarantee that Nato will not expand eastward,” he added.
Western powers have rejected Russia’s demand for a de facto veto on the security arrangements sought by countries in eastern Europe, and have pledged to hit Russia with severe sanctions if it launches a new attack on Ukraine.
Ukrainian officials said they suspected Russian hackers were behind an attack that affected the websites of about 70 government agencies on Friday
"Ukrainian! All your personal data was uploaded to the public network ... be afraid and expect worse," said an on-screen message left by the hackers. Kiev said no personal information was lost and most affected websites were quickly restored.