¡¡WASHINGTON, Dec. 8 (Xinhuanet) -- US officials defended on Thursday the shooting incident on Wednesday in which a plane passenger was killed at Miami International Airport, Florida.

    The two air marshals who shot a 44-year-old American Airlines passenger to death followed "textbook training," said Dave Adams, a spokesman for the air marshals.

    He confirmed that both the two air marshals on aboard the flight fired at Rigoberto Alpizar, after he ran off the plane and ignored demands to stop and put down his bag.

    "We only react when there is a threat to the aircraft, passengers or crew," Adams said.

    The two federal air marshals had been put on administrative leave pending investigation of the incident, officials said.

    Homeland Security spokesman Russ Knocke said the incident "demonstrates the critical role that air marshals play in aviation security today."

    At the White House, spokesman Scott McClellan said the marshals appeared to have acted in a way consistent with their training. The Federal Bureau of Investigation, the Department of Homeland Security and police in Miami were investigating the incident, he said.

    Alpizar, who was reportedly mentally ill, was said to have claimed he had a bomb in his carry-on bag after the American Airlines Flight 924 had arrived in Miami.

    No bomb was found, and federal officials later concluded there was no link to terrorism.

    This was the first time that a passenger has been shot by air marshals since the Sept. 11, 2001, terror attacks.

    The US government employed thousands of air marshals after the attacks, in addition to 33 at that time. Enditem