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9/11: Flight attendant reports stabbing

9 September 2011 Last updated at 11:31 BST

Audio of Betty Ong, a flight attendant on American Airlines Flight 11, speaking to American Airlines reservations agents.

"Somebody's stabbed in business class, and, um I think there is Mace that we can't breathe," Ms Ong says. "I don't know, I think we're getting hijacked."

9/11 timeline: The story of the day