(Reuters) – U.S. wireless operators on Wednesday fought back against an accusation from the New York State attorney general that they refused to install software that would act as a kill switch to discourage theft of smartphones. New York Attorney General Eric Schneiderman sent letters to top executives of ATT Inc, Verizon Wireless, Sprint Corp, T-Mobile US Inc and U.S. Cellular Corp, asking why they prevented Samsung Electronics Co from putting kill switch technology in their smartphones.