The Israeli military published a brief video on Thursday aimed at showing that a Palestinian medic killed by Israeli forces last week was not the neutral health care worker she has been portrayed as.

The tightly edited video shows a woman identified as the medic, Rouzan al-Najjar, throwing what appears to be a tear-gas canister. The video does not appear to have been taken the day Ms. Najjar was killed, and the canister does not appear to be aimed at anyone.

In a second scene, according to the video, Ms. Najjar tells an interviewer, “I am here on the front line and I act as a human shield.”

Since she was killed at a protest at the Gaza-Israel border fence last Friday, Ms. Najjar, who was 20, has become a powerful symbol of the conflict there. Hamas, the Islamist movement that rules Gaza, has portrayed her as a hero and an innocent victim of Israeli aggression.