United States senators on Tuesday criticised technology companies Facebook, Twitter and Google for not doing more to prevent alleged Russian interference in the American political process, AP reported.

Democrats and some Republicans on a Senate Judiciary subcommittee complained that the companies waited almost a year to publicly admit how many Americans were exposed to alleged Russian effort to spread propaganda during the presidential election last year, The New York Times reported.

While senators such as Amy Klobuchar pushed for harsher rules, including regulations on the technology companies’ advertising practices, the companies’ executives did not offer anything more than promises to do better in the future.

“People are buying ads on your platform with roubles. They are political ads,” Senator Al Franken said. “Google has all knowledge that man has ever developed. You cannot put together roubles with a political ad and go like, ‘Hmmm, those data points spell out something pretty bad?’”

The most pointed remarks, The New York Times reported, were aimed at Facebook, which acknowledged on Monday that over 126 million users may have seen inflammatory political ads bought by a Kremlin-linked company. “In hindsight, we should have had a broader lens,” said Facebook’s general counsel Colin Stretch.

“The abuse of our platform to attempt state-sponsored manipulation of elections is a new challenge for us – and one that we are determined to meet,” Twitter’s acting general counsel Sean Edgett was quoted as saying by AP.