In the interrogation, Mr. Khadr said he wanted to return to Canada, but the agent suggested that the situation was so good in Cuba he might want to stay there himself. “The weather’s nice,” the interrogator said. “No snow.”

Mr. Khadr, who had been shot and was near death at the time of his capture in Afghanistan, repeatedly complained about his medical treatment and physical condition. At one point, he lifted his shirt to show the agent the wounds on his back and stomach.

The agent, however, was unmoved. “I’m not a doctor, but I think you’re getting good medical care,” he responded.

Later, a sobbing Mr. Khadr said, “You don’t care about me.”

Slats, apparently from a ventilation panel in the detention center, obscure parts of the images.

In a statement regarding the tapes, a Pentagon spokesman, Cmdr. Jeffrey D. Gordon, offered only a blanket defense of the detainees’ treatment. “Guantánamo provides an environment for detainees that is stable, secure, safe and humane,” it said. “This environment sets the conditions to successfully gain valuable information from detainees built on a relationship of trust, not fear.”

The statement called it “commonplace” for interrogators seeking to establish rapport with detainees to share “a meal from Subway or McDonald’s.”