The First Viewer was not pleased.
But the object of his ire was not CNN or MSNBC. It was his favorite outlet, Fox News Channel, and the president issued a not-so-veiled threat about the network's programming.
No president has been so closely aligned with a single news outlet as Trump is with Fox News, so his criticism carried added significance. While it was not the first time he has singled out Fox, it was the most pointed, raising the question of how the network, and the president's supporters, would respond.
Trump on Sunday night wrote that watching Fox on the weekend was worse than watching CNN and MSNBC, outlets he frequently attacks. He said Fox is "loading up with Democrats" and criticized the network for using The New York Times as a source for a story. He also attacked Fox for hiring former Democratic National Committee head Donna Brazile as a contributor and poked at afternoon host Shepard Smith's ratings.
"Fox News is changing fast, but they forgot the people who got them there," Trump wrote.
Fox did not immediately respond to requests for comment.
While it was not clear what Trump was specifically responding to, he was particularly annoyed by Fox correspondent Greg Palkot's live report from a sports bar in France, where patrons erupted in a "F--- Trump" chant, according to two advisers not authorized to speak publicly about private discussions.
Fox also aired two segments about immigration Sunday that used as a hook a Times story that said workers at a child detention center in Texas are "grappling with the stuff of nightmares," according to Matthew Gertz of the liberal watchdog Media Matters for America.
By some measures, Trump has never been closer to Fox News, or at least their evening hosts. He regularly calls into Sean Hannity's show, touts Laura Ingraham's program and, last month, frequently consulted Tucker Carlson, who strongly opposes military action against Iran, off-air. A few days later, Carlson was spotted among Trump's entourage during the president's visit to the demilitarized zone between North Korea and South Korea. Carlson traveled with Trump for an interview that was shown on Fox.
But the president's frustration with the network has grown in recent months.
He has angrily told confidants he is confused about why Fox News sometimes "goes negative" in its coverage of his administration when it features an unflattering portrait of his White House, the advisers said.
Trump was particularly annoyed at Fox's coverage when he saw his ties to billionaire financier Jeffrey Epstein being played up on the other networks.
Epstein was charged Monday with sexually abusing dozens of underage girls. His powerful friends over the years have included Trump, former President Bill Clinton and Britain's Prince Andrew.
Trump has gone on to complain that he feels that MSNBC and CNN rarely criticize Democrats and instead deliver pointed and, in his estimation, unfair attacks on the administration. To counter that, Trump has said, he feels it is important for Fox News to remain "loyal" to the White House and Republicans as a balance to the other networks' alleged bias, according to the advisers.
"I think he takes 'Fox & Friends' literally, that they're supposed to be friends," said Frank Sesno, director of the School of Media and Public Affairs at George Washington University. "Fox has real journalists who ask real questions, like Chris Wallace. If he thinks the 'no spin zone' is going to be the no criticism zone, he's right most of the time, but not all of the time."
Trump tweeted negatively about Fox this spring after it aired town halls featuring Democratic presidential candidates Bernie Sanders and Pete Buttigieg. "Fox is moving more and more to the losing (wrong) side in covering the Dems," he tweeted May 19.
He said "what's with Fox News?" on April 16 after the Sanders session, accusing the network of turning away Trump fans who wanted to attend.
In March, he suggested Fox weekend anchors Arthel Neville and Leland Vittert should be working at CNN.
"I suspect Fox executives don't get too worked up over the president's tweets and offhanded comments," said Ken LaCorte, a longtime Fox News executive who now operates his own website. News reporters and anchors at Fox, who work in the shadow of opinion hosts, don't necessarily mind when a presidential tweet illustrates that not everyone at Fox is in the president's pocket.
Still, many of Fox's regular viewers also follow Trump on Twitter, and there's a risk when the president foments discontent. LaCorte said if the crticisms became more frequent, or if Trump cuts off the frequent access that many Fox personalities have for interviews, that would be a more worrisome sign.
Sesno, however, said the latest incident foreshadows potential trouble for Fox as the campaign heats up. Trump will obviously come under criticism; to what extent does Fox reflect that?
While there are other conservative websites and news networks, like One American News Network and NewsMax, none come close to the reach and influence that Fox has with this audience.
"What other channel are you going to if you want to see pro-Trump stuff on TV?" Sesno asked.