The Biden administration believes Russian government hackers were behind cyberattacks targeting Ukraine’s Ministry of Defense and banks in Ukraine earlier this week, a top White House official said Friday.  

White House deputy national security adviser for cyber and emerging technology Anne Neuberger told reporters the U.S. believes that hackers working with Russia’s military intelligence directorate, or GRU, are responsible for distributed denial-of-service (DDoS) attacks reported in Ukraine this week.

Neuberger said the Biden administration has “technical information” linking the attacks to the GRU and the U.S. shared underlying intelligence supporting the attribution with Ukraine.  

“We have assessed that Russia was responsible for the distributed denial-of-service attacks that occurred earlier this week,” Neuberger said.  

Neuberger added that the U.S. worked to attribute the attacks quickly because of the need to call Russia out for its behavior.

“The speed with which we made that attribution ... is very unusual,” she said. “And we’ve done so because of a need to call out the behavior quickly, as part of holding nations accountable when they conduct disruptive or destabilizing cyber activity.” 

Neuberger said the “limited” attacks could be consistent with an effort by Russia to lay the groundwork for more disruptive cyberattacks on Ukraine.  

Ukraine reported the cyberattacks earlier this week amid fears of a Russian invasion of Ukraine and said Russia was the likely culprit.

Biden administration officials have warned that Russia could launch a cyberattack on Ukraine in tandem with or instead of an invasion.  

The U.S. has estimated that Russia has between 169,000 and 190,000 military personnel in and around Ukraine, including troops positioned at its border with Ukraine, in Belarus and in Russian-occupied Crimea. 

Neuberger said Friday that the U.S. has been helping Ukraine prepare for disruptive or destructive cyberattacks against Ukraine by Russia in the event of an invasion. 

She said the U.S. believes Russian hackers have likely been targeting Ukraine government networks both to collect intelligence and to lay the groundwork for carrying out cyberattacks. 

“These disruptive cyber operations could be leveraged if Russia takes further military action against Ukraine,” Neuberger said.  

Russia has increasingly used cyberattacks as an asymmetric tool against the U.S. and other countries, including Ukraine.   

President Biden said earlier this week that his administration was prepared to respond to Russian cyberattacks against the U.S. or its allies.  

“If Russia attacks the United States or our Allies through asymmetric means, like disruptive cyberattacks against our companies or critical infrastructure, we are prepared to respond,” he said during a speech at the White House.  

Neuberger said that the U.S. has been preparing for potential cyberattacks against the U.S., Ukraine and other allied countries since November. She noted there are currently "no specific or credible cyber threats to the homeland.”

Updated at 4:14 p.m.