OSTERSUND, Sweden — A Swedish student activist stopped the deportation of an Afghan man this week by refusing to take her seat on a packed Turkish Airlines flight, and her dramatic video of the tense standoff has gone viral.

The student, Elin Ersson, initially bought a ticket because she believed that a 26-year-old man from Afghanistan was being deported to Kabul from Landvetter Airport in Gothenburg via Istanbul. When she got on the plane, the 26-year-old was not there, but an Afghan deportee in his 50s was with the Swedish authorities.

Ms. Ersson, 21, live-streamed the standoff on the flight late Monday on Facebook, and footage of the 14-minute video shows her in tears, at times being confronted by crew members and angry passengers. But she also garnered some support.

“I’m not going to sit down until this person is off the plane,” she says in the video, “because he is most likely to get killed if he is on this plane when it goes up.”