US President Donald Trump, in a series of early morning Twitter posts Tuesday, attacked Google for what he claimed was an effort to suppress conservative news outlets supportive of his administration.

Trump’s remarks—and an additional warning later in the day that Google, Facebook and Twitter “have to be careful"—escalated a conservative campaign against the internet industry that has become more pointed since Apple, Google and Facebook removed content from Alex Jones, a right-wing conspiracy theorist who runs the site Infowars and has been a vocal supporter of Trump.

“Google search results for ‘Trump News’ shows only the viewing/reporting of Fake New Media," Trump said on Twitter at 5:24 a.m. “In other words, they have it RIGGED, for me & others, so that almost all stories & news is BAD. Fake CNN is prominent." Trump added that “they are controlling what we can & cannot see. This is a very serious situation-will be addressed!"

Larry Kudlow, the director of the National Economic Council and a longtime advocate of deregulation, appeared to back Trump when asked by reporters later Tuesday whether the administration would be pursuing more regulation of Google. “We’ll let you know," Kudlow said. “We’re taking a look at it."

In a statement, Google said that its search service was “not used to set a political agenda and we don’t bias our results toward any political ideology."

The president’s tweets landed at a difficult moment for the tech industry. There is a growing sense across the United States and elsewhere that something must be done to rein in their influence.

Executives from many of the largest internet companies will face questions next week at a Senate Intelligence Committee hearing about their efforts to prevent foreign meddling in the midterm elections in November.

Interfering in how companies like Google and Facebook present information would be a notable departure for the federal government, which has mostly taken a hands-off approach to the internet. Free-speech scholars said companies like Google and Facebook were free to operate with few restrictions thanks to a 1996 law called the Telecommunications Act.

“That law pretty much removes free-speech liability for Google and Facebook," said Roy Gutterman, director of the Tully Center for Free Speech at the Newhouse School. “That being said, I think it’d be a major leap to believe that the people behind Google are writing algorithms to discriminate against content."