The denials came after NBC News reported US President Joe Biden was offered options that included the use of American cyberweapons "on a scale never before contemplated."
Reporters for NBC News claimed they were told by two US intelligence officials, one Western intelligence official, and another person briefed on the matter that Biden was given options such as shutting off electric power in Russia, disrupting the country's internet connectivity, and damaging railroad switches.
One official claimed the US could "do everything from slow the trains down to have them fall off the tracks."
Within an hour of the story being published, multiple White House officials came out against it, denying its accuracy. White House spokesperson Emily Horne called the story "wildly off base."
"This report on cyber options being presented to [the President] is off base and does not reflect what is actually being discussed in any shape or form," said White House Press Secretary Jen Psaki.
The NBC report noted that some US officials believe if the cyberattacks simply disrupt systems and refrain from the destroying them, they will fall short of being considered "acts of war." According to the sources that spoke to NBC, the US government would not publicly take credit for the attacks and would most likely make them covertly.
The denials came before Biden spoke to the press and discussed how the US may respond if cyberattacks expand beyond Ukraine and affect US organizations.
"If Russia pursues cyberattacks against our companies, our critical infrastructure, we're prepared to respond. For months, we've been working closely with the private sector to harden our cyber defenses [and] sharpen our response to Russian cyberattacks," Biden told reporters on Thursday.
He noted that the Ukraine State Cyber Protection Center, Secretariat of the Cabinet of Ministers of Ukraine, and another platform that hosts some Ukrainian government sites are facing the most DDoS attacks.
"The internet of Ukraine is under severe stress presently. Following the initiation of hostilities last night, we began seeing sporadic outages across the country. At the same time, the DDoS attacks directed against Ukrainian institutions that began last week are continuing," Madory said.
Netblocks has also confirmed a number of outages throughout Ukraine since the invasion began, including ones in major cities like Kharkiv and Mariupol.
Russia released its own alert about potential cyberattacks, warning that "in the current tense geopolitical situation, we expect an increase in the intensity of computer attacks on Russian information resources, including critical information infrastructure facilities."
Many experts urged restraint on both sides, warning that cyberattacks on infrastructure have been a red line that few countries have crossed. Coalfire Field CISO John Hellickson said launching a cyberattack would set a dangerous precedent going forward.
"Would this cyberattack be considered a direct act of war?" Hellickson asked.
"Given the challenges in executing strong cybersecurity across critical infrastructure here at home, a retaliation by Russia and/or their sympathetic allies could have devasting impacts on these services that Americans rely upon. I believe we need to avoid crossing the line of such considerations as it's difficult to predict the impacts of a likely retaliation."