Mr Gonzales highlighted the problem of adults preying on children in chat rooms and networking sites with the purpose of making sexual contact.

He quoted a study that said one in every five children is solicited online.

"It is simply astonishing how many predators there are, and how aggressive they act," he said.

Out of control

In his speech, Mr Gonzales also detailed examples of graphic sexual and physical abuse investigated by the US Immigrations and Customs Enforcement.

It included what he described as "molestation on demand", where a child is abused as others watch live through streaming video.

Some of the offences were committed abroad but viewed by people in the US.

New technology such as file-sharing meant that law enforcement agencies are no longer able to control child pornography.

"Sadly, the internet age has created a vicious cycle in which child pornography continually becomes more widespread, more graphic, more sadistic, using younger and younger children," he said.

Legal action

In response, he announced proposed changes in the law under the Child Pornography and Obscenity Prevention Amendments of 2006.

The proposals have been sent to Congress and include new laws that will require ISPs to report child pornography and bolster penalties for those companies that fail to do so.

Mr Gonzales also said that he is also investigating ways to ensure that ISPs retain records of a user's web activities to track down offenders.

"The investigation and prosecution of child predators depends critically on the availability of evidence that is often in the hands of internet service providers," he said.

"Unfortunately, the failure of some internet service providers to keep records has hampered our ability to conduct investigations in this area."

In the UK some ISP's have already taken the initiative on this issue.

Companies like BT already block access to sites it believes contain child pornography.

The telecoms giant says that its servers block 35,000 attempts to view child porn each day