Trump, in tussle with CNN, suggests boycott of parent AT&T President Donald Trump took to Twitter on Monday immediately after he arrived in London for a pomp-filled state visit to Britain to complain about CNN

NEW YORK -- President Donald Trump took to on Monday to reiterate his complaints about CNN and suggest a boycott of its parent company, AT&T.

Soon after his arrival in London for a pomp-filled state visit, Trump tweeted that CNN is the primary source of U.S. news in the United Kingdom. "After watching it for a short while, I turned it off," he wrote. "All negative & so much Fake News, very bad for U.S."

Trump asked why doesn't AT&T "do something" and said that if people stopped using or subscribing to AT&T, it would be forced to make "big changes" at CNN. CNN is owned by Turner Broadcasting System, a division of AT&T's WarnerMedia.

"This is unprecedented and extremely unusual for this to come out of 1600 Pennsylvania Avenue," said Daniel Ives, an analyst with Wedbush Securities.

It's not clear how much of an impact Trump's remarks will have. Invested shrugged off the news, as AT&T's stock price increased 1.7% on Monday. AT&T and CNN declined to comment.

Trump has suggested boycotting companies he has had grievances with in the past, both before and after he became president.

Trump, for instance, called on people to boycott Apple in 2016 after it rebuffed the FBI's efforts to require a security backdoor into iPhone technology. Though Apple has seen iPhone sales decline, analysts point to an industry-wide slowdown in innovation, which has prompted people to wait longer between upgrades.

Other boycott targets have included Macy's , Harley-Davidson and HBO , which AT&T later acquired with CNN as part of its $81 billion purchase of Time Warner Inc.

Trump has long criticized CNN over its coverage of him and his administration. Fox News Channel is his preferred network.

While unusual, the extension of Trump's CNN complaints to its parent company isn't surprising. When AT&T's bid for Time Warner became public in 2016, it drew fire from then-candidate Trump, who promised to kill it "because it's too much concentration of power in the hands of too few."

After he became president, the Justice Department sued to block AT&T's bid for Time Warner, arguing it would hurt consumers . The president's statements didn't come up during the trial, though his antipathy loomed in the background.

A judge ultimately ruled in favor of letting the acquisition continue and it was completed in June 2018. The Department of Justice lost an appeal in February . The department declined to appeal further to the Supreme Court, where its chances of prevailing were considered dim.