US Secretary of State Hillary Clinton promised on Wednesday that the United States will use the Internet and social media in its fight against al-Qaida and other extremist groups.

The outgoing top diplomat said the US State Department had "started two organizations to deal with countering violent extremism" on the Internet, and will use tools such as the Twitter micro-blogging site to combat online anti-Americanism.

"Social media is a great tool," Clinton told lawmakers when speaking to Congress about the deadly attack on a US mission in Benghazi, Libya, four months ago.

The new operation she has set up is "staffed with inter-agency experts," and "I'm not saying anything that's classified, but it's beginning to try to respond to al-Qaida and other jihadist propaganda.

"If they put up a video which talks about how terrible US citizens are, we put up a video which talks about, you know, how terrible they are," Clinton said.

"We're trying to meet them in the media channels (in which) they are communicating with people."

Referring to the Cold War era, Clinton said media tactics had worked well, and that in 2013 the US will confront a similar challenge with an up-to-date strategy.

Agence France-Presse