July 13, 2008 (23 images)

Updated: July 14, 2008 at 10:15 AM
1 of 23
Chinese construction workers stand on scaffolding erected to build an Olympic-themed exhibit on Tiananmen Square in central Beijing July 13, 2008. China vowed Sunday to step up security for the upcoming Olympics, warning of an unprecedented threat to the Games amid reports that two "terrorists" were executed in the mainly Muslim far northwest. (UPI Photo/Stephen Shaver)
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