WASHINGTON — After teen climate activist Greta Thunberg delivered an emotional speech to world leaders at the United Nations in New York City on Monday, news cameras captured her staring at President Donald Trump when he arrived in the same lobby she was in.

The stare at the UN comes days after millions of people around the world took part in Friday's climate strike that Thunberg helped organize.

"Around the world today about 4 million people have been striking," Thunberg said of the protests. "This is the biggest climate strike ever in history and we all should be so proud of ourselves because we have done this together."

The video of the 16-year-old Swede staring directly at Trump went viral on Monday, with social media users making the interaction into a GIF.

Previously, Trump skipped a G-7 session focused on climate in August where the rest of the G-7 leaders were present, reportedly telling aides that the meeting of world leaders was focused too intensely on climate and other environmental issues.

Trump has been at odds with world leaders specifically on climate after he announced in 2017 that the U.S. would formally withdraw from the Paris climate agreement. He made an unexpected appearance at the UN climate summit Monday, for a total of 14 minutes.

Thunberg’s scolded hundreds of world leaders at the UN saying through tears, "how dare you! You have stolen my dreams and my childhood with your empty words, and yet, I am one of the lucky ones.”

“How dare you continue to look away and come here saying that you are doing enough when the politics and solutions needed are still nowhere in sight."

Last week, Thunberg told lawmakers on Capitol Hill that she wanted them to “listen to the scientists. And I want you to unite behind the science. And then I want you to take real action."

Instead of planning a lengthy opening statement to start the hearing, Thunberg simply offered a copy of the 2018 global warming report by the Intergovernmental Panel on Climate Change that emphasizes the dire threat that human-caused global warming poses, along with the climate and economic impacts.

She recently said during an interview with NPR that the United States has an “enormous responsibility" to lead climate efforts.

"People are suffering, people are dying, entire ecosystems are collapsing. We are in the beginning of the mass extinction and all you can talk about is money and fairytales of eternal economic growth. How dare you?” Thunberg pleaded Monday at the UN.

In August, Thunberg captured global attention when she set off from Plymouth, United Kingdom, on a two-week zero-emissions boat voyage across the Atlantic to New York City. Thunberg wouldn't fly to the U.S. because of emissions from air travel.

Thunberg told world leaders Monday: “You are failing us. But the young people are starting to understand your betrayal. The eyes of all future generations are upon you. And if you choose to fail us, I say: We will never forgive you."

"We will not let you get away with this. Right here, right now is where we draw the line. The world is waking up. And change is coming, whether you like it or not," she concluded.

Contributing: Christal Hayes, Grace Hauck, John Fritze and Michael Collins.