WASHINGTON — President Donald Trump attacked 16-year-old environmental activist Greta Thunberg on Thursday for being named Time magazine's "Person of The Year."

"So ridiculous," Trump said on Twitter. "Greta must work on her Anger Management problem, then go to a good old fashioned movie with a friend! Chill Greta, Chill!"

Thunberg responded swiftly, changing her Twitter profile to read: "A teenager working on her anger management problem. Currently chilling and watching a good old fashioned movie with a friend."

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Trump, who was named Person of the Year after winning the 2016 presidential election, has criticized the magazine before for passing him up in the years since.

Trump mocked Thunberg back in September, when both were in New York City for meetings at the United Nations.

Citing lines from Thunberg's address to the Climate Action Summit — the teenager said "people are dying" and "we are in the beginning of a mass extinction" — Trump issued a late-night snarky tweet.

"She seems like a very happy young girl looking forward to a bright and wonderful future," Trump wrote. "'So nice to see!"

So ridiculous. Greta must work on her Anger Management problem, then go to a good old fashioned movie with a friend! Chill Greta, Chill! https://t.co/M8ZtS8okzE — Donald J. Trump (@realDonaldTrump) December 12, 2019

Thunberg dismissed Trump's comments, and said later she wouldn't consider meeting with the U.S. president on the issue of climate change.

"I don’t understand why I would do that," Thunberg said last month on "The Ellen DeGeneres Show." "I don’t see what I could tell him that he hasn’t already heard, and I just think it would be a waste of time, really."

Thunberg has spoken about her diagnosis of Asperger's, a neurological disorder that creates difficulty with social and communications skills. She calls it her "superpower."'

In naming her Person of the Year, Time magazine said "Thunberg began a global movement by skipping school: starting in August 2018, she spent her days camped out in front of the Swedish Parliament, holding a sign painted in black letters on a white background that read Skolstrejk för klimatet: “School Strike for Climate.”

It added: "In the 16 months since, she has addressed heads of state at the U.N., met with the Pope, sparred with the President of the United States and inspired 4 million people to join the global climate strike on September 20, 2019, in what was the largest climate demonstration in human history."

On social media, critics described Trump's tweet as equivalent to bullying a child.

"The President of the United States is attacking a child," tweeted former federal prosecutor and legal commentator Renato Mariotti.

Former White House Communications Director Anthony Scaramucci, now a fierce critic of Trump, called him "a bully and a punk" for attacking Thunberg.

"No normal person would find this sort of behavior tolerable," he tweeted. "Much less from a global leader. @realDonaldTrump is a despicable person."

This article originally appeared on USA TODAY: Trump attacks Greta Thunberg for being Time's 'Person of the Year'