Reports of child abuse pictures on the internet have risen sharply, prompting calls for greater international co-operation to tackle the problem.
Most child abuse sites are hosted in the US
The Internet Watch Foundation (IWF) received 14,313 reports of suspect material between January and June 2006, a rise of 24% on the year before.
Of those websites investigated, nearly 5,000 contained potentially illegal content, an increase of 50%.
However, just 0.2% of child abuse pictures were on UK-based sites.
This is compared with 18% in 1997.
The IWF, in its half year report, said up to half of all child abuse content was traced to the US, 15% to Russia, 12% to Japan and 9% to Spain.
Its chief executive Peter Robbins said 2006 was the organisation's "busiest year yet".
However, he said the rise could be attributed to a growing public awareness and intolerance of such sites.
The IWF, which is funded by the UK internet industry and the European Union, runs a hotline which takes reports of suspect material from members of the public and IT professionals.
Home Office minister Vernon Coaker said greater international action is needed.
He said: "It is crucial to raise awareness among UK internet users about the IWF as the vehicle to report their inadvertent exposure to this type of content."
The IWF's report also revealed some foreign websites carrying child abuse remain accessible for up to five years, despite being reported to the authorities.
It also highlighted a growing trend for message boards and online photo album services to be used to carry images of child abuse.