The site says they have in their possession a written ruling by the judge saying there was "a strong risk of the children's abduction and retention in the United States."
The judge's reasoning may have been influenced by the fact that Kelly failed to return her kids to Monaco following their summer stay in the States. At that time a New York judge ordered them back to Europe to live with their father.
Kelly and Daniel married in August 2006 and welcomed their son Hermes two months later. She filed for divorce in December 2008, while pregnant with their daughter Helena.