The CIA says seven of its employees were killed and six others wounded in a terrorist attack on an agency base in Afghanistan.CIA director Leon Panetta said those killed in Wednesday's attack "were far from home and close to the enemy, doing the hard work that must be done to protect our country from terrorism." His comments came in a message to agency employees sent on Thursday.The attack by a suicide bomber at a Forward Operating Base in Afghanistan's southeastern Khost Province is believed to be one of the worst against the CIA in the agency's history.