WASHINGTON – Secretary of State Hillary Rodham Clinton, addressing criticism of the Obama administration's handling of a deadly attack on U.S. consulate in Libya, on Friday defended the need for American diplomats and aid workers in the Arab world's young democracies, even amid a growing threat from al-Qaida spinoffs.

"We will not retreat," she said in a speech at a Washington think tank.

"We will never prevent every act of violence or terrorism, or achieve perfect security," Clinton said. "Our people can't live in bunkers and do their jobs. But it is our solemn responsibility to constantly improve, to reduce the risks our people face and make sure they have the resources they need to do their jobs."