U.S. President Donald Trump said Tuesday that Google, Twitter and Facebook were "treading on very, very troubled territory" and warned them to "be careful."
Trump made the comments just hours after igniting controversy with a series of early-morning tweets claiming Google search results are "rigged" to turn up news unfavorable to the president's administration.
The president asserted that people were complaining about biased results from social media searches.
"We have literally thousands and thousands of complaints coming in," the president said. "You just can't do that."
In response to a reporter's question in the Oval Office, Trump singled out Google, Facebook and Twitter for criticism and said, "You can't do that to people."
"Google is really taking advantage of a lot of people," the president said. "They better be careful."
Google responded to Trump's earlier criticism by saying its search engine is not used to promote any political agenda.
The company's statement Tuesday said, "We never rank search results to manipulate political sentiment." It also said its major goal was to give users "the most relevant answers in a matter of seconds."
In the early-morning tweets, Trump said Google was "suppressing" conservative voices and "hiding information" that would be more flattering to the president. He also said, "This is a very serious situation — will be addressed!"
Trump tweeted that a search for "Trump news" "shows only the viewing/reporting of Fake New Media [sic]. In other words, they have it RIGGED, for me & others, so that almost all stories & news is BAD."
In addition, the president said 96 percent of those search results were from "National Left-Wing Media." He did not cite a source for that statistic.
New York Times reporter Adam Satariano wrote Tuesday that Trump might have based his claims on comments that Fox Business Network host Lou Dobbs made late Monday. Dobbs reported on comments by the conservative website PJ Media, which said it had conducted an "unscientific study" showing 96 percent of Google search results for the word "Trump" came from what it called "left-leaning sites."
Questioned later in the day about the president's allegations, White House economic adviser Larry Kudlow told reporters, "We're taking a look at it."
U.S. Representative Ted Lieu, a California Democrat who is a frequent critic of the president, responded to Trump's comments by tweeting, "House Judiciary Committee held two hearings on this issue ... Private companies can do whatever they want with speech. What would be illegal is government regulating speech content or speech algorithms."
Zach Graves, head of policy at Lincoln Network, a think tank in Washington, said PJ Media had drawn flawed conclusions about Google in its unscientific study.
Results 'not surprising'
"I think the mistake they make is not understanding how search engine algorithms typically work," Graves told VOA on Tuesday. He said one of the ways the sites are ranked in search results is the number of other web pages that link to it — a measure of how well-used a site is and how many other sites trust its information.
"With that in mind," Graves said, "it's not surprising at all that these big popular media outlets" such as CNN, The New York Times and Fox News "are outranking more niche conservative platforms like Hot Air, the Blaze, and so on."
Data from media analysis firm Alexa.com, a subsidiary of media giant Amazon, show that 303,995 other sites link to The New York Times — the term is "backlink" — while CNN has 210,373 backlinks and Fox News has 76,164. The conservative Wall Street Journal has 128,015 backlinks, while PJ Media itself has 3,807.
"The interpretation is that there's some kind of conspiracy, that Google's coming in and manipulating these results for political reasons," Graves said. "I think the correct interpretation is that this is a natural byproduct of the metrics that the algorithm uses."
He added, however, that he thought Google would do itself a favor to be more transparent about its search algorithm and reach out to conservative groups to assuage their concerns about bias.
VOA's Steve Herman contributed to this report.