FBI Director Robert Mueller spoke about cyber threats along with how the U.S. is working with partners around the world to tackle them, during a keynote address at the annual RSA computer security conference in San Francisco on Thursday.

The Director said U.S. intelligence indicates the threat of cyber terror is “real and rapidly expanding,” including the rise of extremist websites to recruit, radicalize, and incite violence.

Terrorists have yet to launch a full-scale cyber strike, but have “executed numerous denial-of-service attacks” and even defaced the website of the U.S. Congress following President Obama’s recent State of the Union address. The Director told the crowd of cyber professionals that al Qaeda and other extremists “have shown a clear interest in pursuing hacking skills.”

According to the Director, the FBI’s cyber capabilities and partnerships include:

*Cyber squads in each field office nationwide, with over 1,000 specially trained agents, analysts, and digital forensic examiners who run complex undercover operations, share intelligence with law enforcement and intelligence partners, and provide training to counterparts around the world;

*More than 60 overseas offices-called legal attachs-that share information and coordinate joint investigations with their host countries;

*Agents embedded with police forces in Romania, Estonia, the Netherlands, and other countries; and

*Mobile Cyber Action Teams-highly-trained groups of agents, analysts, and experts in both computer forensics and malicious code who travel the world to respond to fast-moving cyber threats.

The Director stressed the relationship with the private sector is vital in reporting breaches of cyber security. “No one country, company, or agency can stop cyber crime,” he said.

“A ‘bar the windows and bolt the doors’ mentality will not ensure our collective safety. We must start at the source; we must find those responsible.”