Prime minister David Cameron says UK and US intelligence agencies will help fight child abuse images on the dark web that is inaccessible to search engines.
Under pressure from the UK government, Google and Microsoft have announced measures to make it more difficult to find child abuse images online.
Child protection experts have warned that most illegal abuse images cannot be found through normal web searches because they are hidden on encrypted peer-to-peer networks.
But Cameron told the BBC's Jeremy Vine that the dark web can be policed, and that the skills of the intelligence communities in the UK and US will be harnessed to do so.
The prime minister said intelligence agencies have developed capabilities to get into the dark internet and decrypt files that are encrypted.
“If you use the best brains – the inheritors to the people that decrypted the Enigma code in the Second World War – if you take those brains, and apply it to the problem of tackling child abuse online, you'll get results,” he said.
Cameron said he was confident of progress after talking to internet service providers (ISPs) and the National Crime Agency (NCA) team that will work with US counterparts to apply the best expertise.
More on UK internet crackdown
Asked about the potential invasion of privacy that would result from the move, he said: "People understand that a crime is a crime whether it's committed on the street or the internet."
Google and Microsoft have agreed to work with the NCA and the Internet Watch Foundation (IWF) in the UK to provide technical support in finding abuse images on the dark web, according to The Guardian.
News of the arrests came a week after the FBI shut down the website and arrested kingpin Ross Ulbricht in San Francisco and one of the site’s top sellers in Seattle.
At the time, Andy Archibald, head of the NCA’s National Cyber Crime Unit (NCCU), said the investigation into Silk Road would provide insights into how criminals use the hidden internet.
These criminal areas of the internet, he said, are also used for fraud and trafficking in people and other illicit goods such as firearms and images of child abuse.