A code connected to Russian hacking efforts has been discovered in a utility system in Vermont in the United States, which could point to vulnerabilities in the US electrical grid, The Washington Post has reported.
The code detected in the northeastern state's system did not disrupt its operations, the paper cited US officials as saying.
The code was associated with the Russian hacking efforts that US officials have dubbed 'Grizzly Steppe'.
The Burlington Electric Department said it had been alerted by the government on Thursday night, carried out a scan and found the malware in one laptop not connected to its grid systems.
It said it took action to isolate that laptop.
US authorities have not yet pinpointed why the Russians targeted the grid, according to the Post, but that it "may have been designed to disrupt the utility's operations or as a test by the Russians to see whether they could penetrate a portion of the grid".
In December 2015, a power failure that plunged parts of western Ukraine into the dark was found to be caused by a cyber attack.
The Russians were accused of causing the blackout, an allegation they have denied.
A US federal law enforcement report released this week showed that Russian intelligence agencies over the last two years blanketed Democratic Party targets with malicious emails and have likely continued such efforts after November's elections.
The report's release followed an array of measures unveiled by Washington as retribution for what US officials have described as Moscow's malicious efforts to tip the vote in favour of President-elect Donald Trump by stealing embarrassing information from Democratic Party operations and senior party members before releasing it to the news media.