President George W. Bush said Saturday he personally has authorized a secret eavesdropping program in the US more than 30 times since the Sept. 11 attacks and he lashed out at those involved in publicly revealing the program. "This is a highly classified program that is crucial to our national security," he said in a radio address delivered live from the White House's Roosevelt Room. "This authorization is a vital tool in our war against the terrorists. It is critical to saving American lives. The American people expect me to do everything in my power, under our laws and Constitution, to protect them and their civil liberties and that is exactly what I will continue to do as long as I am president of the United States," Bush said.