President Trump, chafing against news coverage he says is unfair, accused search-engine operator Google of suppressing positive stories about him and threatening a government response.

"This is a very serious serious situation — will be addressed," he wrote on Twitter, the social media platform where he has more than 50 million followers. The president and congressional Republicans have all accused tech companies based in liberal-leaning Silicon Valley of suppressing news favorable to them, a claim that firm executives have denied in a number of hearings.

What action the president might attempt wasn't immediately clear. Constitutional guarantees bar the government from restricting freedom of speech or the press, but those don't apply to the actions of private companies or individuals. Google, Facebook, and Twitter have all denied presenting content in a way that favors either end of the political spectrum.

[New: Google to Trump: 'We don't bias our results']

"Google search results for 'Trump News' shows only the viewing/reporting of Fake News Media," the president wrote on Twitter. “In other words, they have it RIGGED, for me & others, so that almost all stories & news is BAD. Fake CNN is prominent. Republican/Conservative & Fair Media is shut out. Illegal?”

Google, based in Mountain View, Calif., denied the president's accusations. The algorithms that power its search engine are updated continuously to make sure they yield the highest-quality results without regard to viewpoint, the company said.

"When users type queries into the Google Search bar, our goal is to make sure they receive the most relevant answers in a matter of seconds," a spokesperson said in a statement. "Search is not used to set a political agenda and we don't bias our results toward any political ideology."

Results aren't ranked to manipulate political sentiment either, the company said — a point many Twitter users themselves made in response to the president's tweets.

[Larry Kudlow: White House 'taking a look at' regulations for Google]

His claim that 96 percent of results on a Google search for "Trump news" came from liberal media organizations mirrored the calculations of a journalist at PJ Media — the right-wing news site originally known as Pajamas Media — who experimented by running a search for "Trump" using the news tab on Google's search bar. An article detailing the findings, which said no conservative-leaning outlet appeared in the first page of results, was published Aug. 25.

“Google & others are suppressing voices of Conservatives and hiding information and news that is good," Trump argued. "They are controlling what we can & cannot see. This is a very serious situation.”

While Trump economic adviser Larry Kudlow said the White House "is looking at" whether Google searches should be regulated, the idea was panned elsewhere.

Trump’s tweets preface testimony next week from representatives of Google, Facebook, and Twitter, who will answer lawmakers' questions about election interference and, likely, censorship.

What Google "and others are doing — Facebook, Twitter — they better be careful," the president said during a press briefing later in the Oval Office. "You can’t do that to people. We have thousands of complaints coming in, and you just can’t do that. Google and Twitter and Facebook are really treading on very, very troubled territory, and they have to be fair."

San Francisco-based Twitter says it enforces its content rules dispassionately, based on violations rather than ideology. Facebook didn't immediately respond to a request for comment.

Conservative concerns about speech suppression have gained momentum as social media platforms, including Google's YouTube, address attempts by overseas intelligence agencies, including Russia's, to manipulate voters in Western democracies as they did in the 2016 presidential election, which Trump won.

Tech companies have made aggressive investments to prevent misuse of their products in the two years since, with Twitter telling Congress in July that it was flagging 9.9 million accounts a week for suspicious activity including false or misleading content.

The company, Facebook, and Google all reported finding accounts linked to Russia's Internet Research Agency, a Kremlin-linked digital propaganda group.

Last week, Facebook shut down 652 pages, accounts, and groups linked to Iran and Russia, while Twitter suspended 284 accounts that appeared to have originated in Iran.

Some of the campaigns had been under investigation for months, Facebook CEO Mark Zuckerberg said, as the company balanced its desire to remove them immediately against efforts to understand the operations better so as to improve Facebook's safeguards.

"Some critics have described the sum of all of this work as a banning of conservative voices," Nick Pickles, Twitter's head of public policy strategy, said in a summer congressional hearing. "These claims are unfounded and false."