NEW YORK (Reuters) - New York City plans to start sifting through earth and debris recovered from the World Trade Center site on Monday to look for the remains of victims from the attacks of September 11, 2001, officials said on Friday. The city’s Office of the Chief Medical Examiner on Friday advised families of the dead about the new sifting operation, the first since 2010, a spokeswoman said in a statement. The Medical Examiner’s office has identified remains of 1,634 people out of 2,752 killed when suicide hijackers crashed into the twin towers, leaving more than 1,000 families without any physical remains of those who died.