US President Joe Biden on Monday warned US companies of intelligence that suggests a Russian "cyber threat", urging US businesses to "immediately" prepare defenses.

"If you have not already done so, I urge our private sector partners to harden your cyber defenses immediately," he said in a statement.

Biden said there is "evolving intelligence" that the Russian government is pondering conducting cyberattacks against the US in response to the wave of Western sanctions slammed at Russia over the crisis in Ukraine. 

Deputy National Security Advisor for Cyber and Emerging Technology Anne Neuberger said in a briefing with reporters that despite the US president's warning "there is no certainty that there will be a cyber incident on critical infrastructure."

She also added that despite government efforts to strengthen its aid in the cybersecurity field, there is still a lot more the government has to do in order for it to have the confidence that it has locked its digital doors.

Biden said the US government will use "every tool" to respond to Russia's cyberattacks, adding that most critical infrastructure in the US is owned and operated by private entities, meaning that the states cannot force them to take certain measures in cybersecurity.

He urged them, however, to "accelerate efforts to lock their digital doors."

This comes at a time Russia has been subjected to a number of cyberattacks targeting different facilities. Last week, the website of the Russian foreign ministry is under DDoS attacks around the clock, Russian Foreign Ministry Spokesperson said.

"The [ministry's] website, like the websites of other government agencies, has been under DDoS attacks around the clock for these couple of weeks," Zakharova told the Solovyov Live show on YouTube.

Earlier, the National Computer Network Emergency Response Technical Team/Coordination Center of China has reported several cyberattacks since late February.

The breaches all came from abroad the Republic and coincide with the Russian military operation in Ukraine.

Xinhua reported that most of the attacks came from the US to control Chinese computers and utilize them against Russia, Belarus, and Ukraine.

87% of the attacks were to be used against Russia.

At the end of February, the website of the Russian space agency Roscosmos has been subjected to a massive DDoS attack carried out from various IP addresses, after the Anonymous hacker group's declaration of a cyberwar against Russia, the agency's press service said.

"A massive DDoS attack from various IP addresses is being carried out on the website of Roscosmos. It is currently not available for visiting," a representative of the space agency told reporters.

According to NBC, Biden’s administration had been considering interrupting internet connectivity across Russia, turning off the country's electrical power, and messing with train switches to obstruct Moscow's ability to replenish its military, as per their claims.