Criminals are getting more sophisticated and launching more attacks, said the FBI

Internet criminals are getting more sophisticated and are increasing the number of attacks they launch, according to prosecutors in the US.

The FBI recently appointed Shawn Henry to head up the Cyber Division, in a meeting with reporters he revealed that the agency currently has thousands of open cases into cyber crimes and organised attacks.

Henry pointed to one case where international law enforcers had taken down a criminal network that was buying and selling stolen financial information through an online forum.

He revealed that national security was also at stake. As many as two dozen nations have taken an aggressive interest in penetrating US networks in the past year, said Henry.

Malicious activity could come in the form of attacks that deny access to websites, that compromise sensitive information, or that introduce 'botnets' that spread viruses and covertly co-opt computers to carry out data theft, he said.

New groups of hackers are a growing threat as well, banding together in virtual gangs to pool their expertise and carry out coordinated cyber attacks.