“Within 48 hours, our team plastered the same sites with altered versions of the ads that showed the toll Al Qaeda attacks have taken on the Yemeni people,” Clinton said Wednesday.

In response, “Extremists are publicly venting their frustration and asking supporters not to believe everything they read on the Internet,” she said.

Clinton described the cyber effort as part of a larger, multipronged attack on terrorism that goes beyond attacks like the Navy SEAL raid that killed Usama bin Laden to include the propaganda battle, and the longer, slower campaign of diplomats working alongside special operations troops to shore up local governments and economies and train local forces.