AP Photo/Cliff Owen

In a rare glimpse into cyber warfare tactics, a top U.S. official has explicitly acknowledged that the U.S. government hacked into websites run by Al Qaeda's affiliate in Yemen, changing advertisements that boasted about killing Americans into advertisements that underscored the deaths of Muslim civilians in al Qaeda terror attacks.

During her keynote speech at the Special Operations Command gala dinner in Tampa, Florida Wednesday night, Secretary of State Hillary Clinton said that State Dept. specialists attacked sites tied to Al Qaeda in the Arabian Peninsula (AQAP) that were trying to recruit new members by "bragging about killing Americans."

"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," said Clinton. "We can tell our efforts are starting to have an impact because extremists are publicly venting their frustration and asking supporters not to believe everything they read on the internet."

It had been suspected that the U.S. government played some role in shutting down several jihadi web forums earlier this year, but officials from the CIA and counterterrorism community had previously denied any involvement.

Highlighting the government's use of "smart power" to fight extremists, Clinton said that military and civilian specialists around the world are focused on pre-empting, discrediting, and outmaneuvering extremist propaganda. Calling them  "a digital outreach team," Clinton said the specialists are fluent in Urdu, Arabic, and Somali. The group is "already patrolling the web and using social media and other tools to expose al Qaeda's contradictions and abuses, including its continuing brutal attacks on Muslim civilians."

Secretary Clinton also said that under her tenure the State Department has become more active in working with the Defense Department and the intelligence community to use diplomacy as a tool to fight terrorism of all forms and extremist propaganda.

The Bureau of Conflict and Stabilization Operations, according to Clinton, was created to find ways for civilian diplomats and experts to better aid military operations in hot spots. Clinton said the bureau sent a team of experts ahead of the Special Operations mission in Central Africa to talk to village leaders and rebels who would be open to defecting or helping the U.S. find the warlord Joseph Kony.

Clinton said the State Department's Counterterrorism Bureau is currently spearheading a diplomatic campaign around the world working with local governments and leaders to squeeze any funding venues for al Qaeda and its affiliates.  She said the State Department trains nearly 7,000 police, prosecutors and counterterrorism officials from more than 60 countries.

"We're expanding our work with civil society organizations in specific terrorist recruiting hotspots - particular villages, prisons, and schools - to disrupt the process of radicalization by creating jobs, promoting religious tolerance, and amplifying the voices of victims of terrorism," said Clinton.