President Donald Trump is gathering conservative groups at the White House this week for a “summit” on social media that will prominently snub the tech titans who run big platforms on Facebook, Twitter and Google.

It’s a sharp contrast to earlier days in Trump’s tenure when tech executives were occasional celebrity guests at the White House, serving as a fresh indication of the president’s escalating battle with Big Tech.

Now, Trump regularly accuses the big social media platforms of suppressing conservative voices. He has suggested the companies may be acting illegally and should be sued by U.S. regulators.

White House spokesman Judd Deere said the White House conference on Thursday would bring together “digital leaders for a robust conversation on the opportunities and challenges of today’s online environment.”

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But Google, Facebook and Twitter weren’t invited, their representatives confirmed. And their leaders may be more likely to turn up Thursday at an annual media industry conference in Sun Valley, Idaho, a venue oriented more toward high-stakes deal-making than reflections on perceived bias in online communications.

The White House had no comment on why top tech officials weren’t invited or on whether the conference was deliberately scheduled to overlap with the meeting in Idaho.

The White House announced the summit in June, describing it as an event to bring together “digital leaders for a robust conversation on the opportunities and challenges of today’s online environment.”

The Washington Post reported last week that the White House has asked to the event a number of right-wing luminaries who have been extremely critical of social media companies. Some of these individuals have claimed, often without real evidence, that companies like Facebook and Twitter harbor bias against conservatives and censor their speech. The companies have denied those claims.

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Republican lawmakers and conservative media personalities have for years lobbed claims of anti-conservative media bias at Silicon Valley companies.

But Trump has poured fuel on the fire, attacking large technology companies on a regular basis and suggesting they need to be regulated by the government.

In a meeting earlier this year with Jack Dorsey, the Twitter chief executive, Trump asked about his follower size. The president has suggested, without evidence, that Twitter makes it difficult for his supporters to follow him.

In May, the White House launched an online tool in which people can report instances of perceived social media bias.

Republican lawmakers in Congress have also held hearings over the past year in which they have questioned social media executives about their company practices.

Such hearings have often strayed far from being fact-based conversations. At one hearing last year, Republicans invited the pro-Trump social media duo “Diamond & Silk” to testify. The duo spent the hearing spreading misinformation about social media companies. At other hearings, Republican lawmakers have cited information from right-wing sites like The Gateway Pundit to make their points.