Google has reportedly launched an internal investigation into whether any Russian people or organizations used their service to influence US voters during the 2016 presidential election.

The tech company is also speaking with congressional investigators who are probing the Russian interference in the election, according to The Wall Street Journal.

The effort comes as Facebook and Twitter have admitted that Russian actors infiltrated their sites and, posing as US citizens, waged a massive influence campaign.

In addition to Google’s large ad service, the company also runs massive online streaming site YouTube.

It was not clear what kind of actions Google suspects may have taken place.