Hillary Clinton boasts of US cyberwar against al-Qaeda

Mrs Clinton described the cyber effort as part of a larger, multi-pronged attack on terrorism that goes beyond attacks like the Navy SEAL raid that killed Osama bin Laden to include the propaganda battle, and the longer, slower campaign of diplomats.

Mrs Clinton was speaking alongside Admiral Bill McRaven, head of the US Special Operations Command, at a conference of hundreds of US and international special operations commanders.

Their joint appearance was seen as a tacit message to their sometimes warring tribes of troops and diplomats that they must cooperate.

Mrs Clinton said the cyber attack was launched by an interagency group of specialists, including diplomats, special operators and intelligence analysts, housed at the State Department. Called the Centre for Strategic Counterterrorism Communications, its experts patrol the Internet and social media to counter al-Qaeda's attempts to recruit new followers.

"Together, they will work to pre-empt, discredit and outmaneuver extremist propaganda," Clinton said.

Offensive attacks on extremist sites are generally attributed to the Pentagon's Cyber Command, though seldom acknowledged publicly.