US officials warned Wednesday that unnamed hackers have developed tools designed to “gain full system access” to the sensitive computer systems used to operate energy facilities.

The tools could help a hacker get into an industrial computer network and “disrupt critical devices or functions,” according to a joint advisory from the DOE, FBI, NSA, and CISA.

No reports of cyberattacks using the malicious code. But US officials and cybersecurity experts warned that if successful, the malicious software could disrupt critical infrastructure.

They said the hacking tools could allow “lower-skilled cyber actors to emulate higher-skilled actors.”

“We are unable to associate (the hacking tools) with any previously tracked group at this time,” Mandiant analysts added. Their use poses the biggest threat to Ukraine, NATO members, and other states actively opposing Russia’s incursion.