Many questions about U.S. objectives in Afghanistan need to be answered before more American troops are sent there, U.S. Sen. Bob Casey Jr. said Monday.

Casey, in an interview with The Associated Press, said that both military and nonmilitary goals, including an exit strategy and humanitarian aid, should be fully scrutinized by Congress before more soldiers are mobilized. President Barack Obama this month announced the deployment of 17,000 additional U.S. forces.

''I don't think the administration can just say we need 17,000 and we're going to send them without a discussion of what's the rationale for it, how those troops will be used and what's the goal,'' the Pennsylvania Democrat said.