President Joe Biden has made it clear: the U.S. has no plans to send ground troops into Ukraine, but he’s also warned Russian President Vladimir Putin that a Russian attack on the U.S. or its NATO allies could trigger a direct conflict.

So, as Russia continues its assault on Ukraine, U.S. lawmakers are keeping an eye on cyberspace.

“I know that everyone's on high alert in this situation. But as I mentioned, (cyberattacks are) certainly one of the tools in Putin's toolkit,” Maine Sen. Angus King said. “There were some early attacks on Ukrainian banks and a couple of government agencies but nothing like what they're capable of. In terms of things like the power grid, (Russia) took the power grid down in Ukraine. Part of it in 2015. So they have that capability.”

So far, no significant Russian cyberattacks have materialized in the U.S. during the Ukraine war but cybersecurity expert and Georgetown professor Chuck Brooks says the threat is very real.

“Cybersecurity is integral to any country’s defenses right now, because all of our multi-domain warfare requires communication, situational awareness, and cybersecurity is an imperative for all those,” said Brooks, a former advisor to President George W. Bush at the Defense Department.

King, who is a member of both the Senate Intelligence and Armed Services committees, told Spectrum News Maine that the consensus among lawmakers in Washington is that Russian President Vladimir Putin has strategically held back on any U.S. cyberattacks.

“I suspect that unless (Putin) gets really desperate, that he’ll understand that it would be an escalation,” King said.

It would be an escalation that King said could be perceived as an act of war. Right now, the Senator said there’s no “clearly defined doctrine” on what constitutes an act of war in cyberspace but added that it’s something he’s called attention to.

“If (Russia) took down the grid and people froze to death or people died in hospitals, I think that would be considered a major attack,” King said of a potential Russian cyberattack on U.S. infrastructure.  “Joe Biden has told (Putin) this point blank, that a substantial cyberattack on civilian infrastructure in the United States would be met with a serious response and I think he knows that we have equivalent cyber capabilities.”

Meanwhile, Congressman Jake Auchincloss of Massachusetts has been looking at cyberattacks as a means of defense. On Wednesday, he suggested using "deniable, surgical cyberattacks on Russian command & control and logistics nodes within Ukraine.”

Brooks acknowledged that independent hackers have already started their own efforts.

“Groups like Anonymous and many talented hackers from a variety of countries around the world have carried out thousands of attacks on Russian targets,” Brooks said.

Included in the budget bill passed by the House on Thursday night is funding that would help Ukraine shore up its cyber defense. It also includes money that would fund more government support for the U.S. Cybersecurity and Infrastructure Security Agency.