Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Russian government-aligned hackers who penetrated the Democratic Party have spent the past few months laying the groundwork for an espionage campaign against the U.S. Senate, a cybersecurity firm said Friday.

The revelation suggests the group, often nicknamed Fancy Bear, whose hacking campaign scrambled the 2016 U.S. electoral contest, is still busy trying to gather the emails of America's political elite.

"They're still very active — in making preparations at least — to influence public opinion again," said Feike Hacquebord, a security researcher at Trend Micro Inc., which published the report. "They are looking for information they might leak later."

The Senate Sergeant at Arms office, which is responsible for the upper house's security, declined to comment.

Related: Who are the Russian-backed hackers attacking the U.S.?

Get breaking news and insider analysis on the rapidly changing world of media and technology right to your inbox. This site is protected by recaptcha

Hacquebord said he based his report on the discovery of a clutch of suspicious-looking websites dressed up to look like the U.S. Senate's internal email system. He then cross-referenced digital fingerprints associated with those sites to ones used almost exclusively by Fancy Bear, which his Tokyo-based firm dubs "Pawn Storm."

Trend Micro previously drew international attention when it used an identical technique to uncover a set of decoy websites apparently set up to harvest emails from the French presidential candidate Emmanuel Macron's campaign in April 2017. The sites' discovery was followed two months later by a still-unexplained publication of private emails from several Macron staffers in the final days of the race.

Hacquebord said the rogue Senate sites — which were set up in June and September of 2017 — matched their French counterparts.

"That is exactly the way they attacked the Macron campaign in France," he said.

Attribution is extremely tricky in the world of cybersecurity, where hackers routinely use misdirection and red herrings to fool their adversaries. But Tend Micro, which has followed Fancy Bear for years, said there could be no doubt.

"We are 100 percent sure that it can attributed to the Pawn Storm group," said Rik Ferguson, one of the Hacquebord's colleagues.

Like many cybersecurity companies, Trend Micro refuses to speculate publicly on who is behind such groups, referring to Pawn Storm only as having "Russia-related interests." But the U.S. intelligence community alleges that Russia's military intelligence service pulls the hackers' strings and a months-long Associated Press investigation into the group, drawing on a vast database of targets supplied by the cybersecurity firm Secureworks, has determined that the group is closely attuned to the Kremlin's objectives.

If Fancy Bear has targeted the Senate over the past few months, it wouldn't be the first time. An AP analysis of Secureworks' list shows that several staffers there were targeted between 2015 and 2016.

Among them: Robert Zarate, now the foreign policy adviser to Florida Senator Marco Rubio; Josh Holmes, a former chief of staff to Senate Majority Leader Mitch McConnell who now runs a Washington consultancy; and Jason Thielman, the chief of staff to Montana Senator Steve Daines. A Congressional researcher specializing in national security issues was also targeted.