President Donald Trump hit Facebook, Google and Twitter again Tuesday for supposedly siding with his Democratic opponents.

It's a familiar tune for the Republican president, whose administration is preparing antitrust action against Silicon Valley giants, but it comes with some ironic context.

@realDonaldTrump: Facebook, Google and Twitter, not to mention the Corrupt Media, are sooo on the side of the Radical Left Democrats. But fear not, we will win anyway, just like we did before! #MAGA

Trump far outspends his fellow 2020 candidates in social ads on sites like Facebook, according to a tracker maintained by communications agency Bully Pulpit Interactive.

In the week ending March 10, the Trump campaign spent nearly $500,000 on Facebook and Google ads. That dwarfs the second-highest spending — $107,000 by the Democratic presidential campaign of Washington Gov. Jay Inslee.

Trump's campaign has spent roughly $4.5 million this year. Sen. Elizabeth Warren, D-Mass., who announced her 2020 presidential exploratory committee on New Year's Eve, has spent $595,000.

Trump's heavy use of Facebook emerged after the 2016 election as a factor in his success. Trump's 2020 campaign manager, Brad Parscale, was credited with masterminding the president's 2016 social media strategy — but has since become an outspoken critic of Big Tech.

Trump doubled down on this comments later Tuesday during a joint press conference with Brazilian President Jair Bolsonaro, highlighting Twitter as the worst alleged offender.

"Things are happening, names are taken off, people aren't getting through," Trump said. "And it seems to be if they're conservative, if they're Republicans, if they're in a certain group, there's discrimination — big discrimination. I see it absolutely on Twitter, and Facebook, which I have also, and others I see, but I really focus more on the one platform."

Trump suggested the tech companies and media outlets could be working together, and indicated that he would continue looking into the companies.

"I do think we have to get to the bottom of it," he said. "It's collusive, and it's very, very fair to say that we have to do something about it."

The digs at Facebook, Google and Twitter follows a lawsuit by Rep. Devin Nunes, R-Calif., that alleges Twitter allowed defamatory posts about him on the platform as part of a political agenda.

Nunes is hardly the first conservative lawmaker to ding Twitter for supposed political bias, but his is the first major formal lawsuit. The social media platform has faced repeated claims that it removes or buries conservative accounts, a practice sometimes called "shadow banning."

Twitter and CEO Jack Dorsey have maintained it does not take action against accounts based on political ideology.

WATCH: Trump: Google, Facebook, Twitter treading on very troubled territory