US President Barack Obama says he doesn't worry much about his safety because the Secret Service does "an outstanding job" protecting him. Obama told ABC News the 50th anniversary of the assassination of President John F. Kennedy did not arouse any anxiety over the possibility that he too might be the target of an assassin. "It's not something I think about. Mainly because we have a Secret Service that does an outstanding job every single day," the president said Friday in an interview to be aired Nov. 29 on ABC's "20/20." Obama said the death of Kennedy "reshaped the Secret Service in many ways" that have improved presidential safety. The agency, with a staff of nearly 7,000 employees, took steps such as doing away with convertibles as presidential limousines, The Hill said. "They do an outstanding job and it (his safety) is thankfully not something I spend a lot of time worrying about," Obama said.