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Growing speculation that plane was brought down by Russian air defenses

There was growing speculation that an Azerbaijani airliner was shot down by Russian air defense system. Russia had initially said it believed the plane hit a flock of birds, but a U.S. official says it may have been struck by Russian air defenses. 67 people were on the plane, and 29 of them survived. A top Russian official warned against early speculation with the investigation in its infancy. NBC News' Steve Patterson reports.