Sen. Bernie Sanders (I-Vt.) on Tuesday criticized Facebook and Senate Republicans in response to reports of Russia hacking the Ukrainian gas company at the center of the impeachment inquiry into President Trump.

“The 2020 election is likely to be the most consequential election in modern American history, and I am alarmed by new reports that Russia recently hacked into the Ukrainian gas company at the center of the impeachment trial, as well as Russia’s plans to once again meddle in our elections and in our democracy,” the 2020 presidential candidate said in a statement.

Cybersecurity firm Area 1 Security on Monday released a report claiming that hackers affiliated with Russia’s military began a phishing campaign against Burisma Holdings in November.

The efforts to steal email credentials coincided with the House’s investigation into a phone call where Trump pressured Ukrainian President Volodymyr Zelensky to investigate former Vice President Joe Biden and his son Hunter, a former Burisma board member.

The hackers were affiliated with the GRU, the military intelligence unit that used phishing methods to obtain usernames and passwords of Democratic National Committee staff in 2016, according to Area 1.