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US prepares for 9/11 anniversary commemorations

11 September 2011 Last updated at 06:43 BST

The US is preparing to mark the 10th anniversary of the 9/11 attacks on New York, Washington and Pennsylvania.

Commemorations are taking place in all three sites where four hijacked airliners struck, killing nearly 3,000 people.

An official memorial to those who died is to be unveiled at the site of the World Trade Center, whose twin towers were destroyed in the attacks.

Steve Kingstone reports.