The UK, supported by France and Italy, has urged social media companies to speed up the removal of "terrorist content" from the internet. Several websites list ingredients for making bombs, for example.
The average lifetime of so-called "Islamic State" propaganda online has fallen to 36 hours, but is still "too long," British Prime Minister Theresa May told the UN General Assembly of world leaders in New York on Wednesday.
"The tech companies have made significant progress on this issue, but we need to go further and faster to reduce the time it takes to remove terrorist content online," May said. She added there was also a need "to increase significantly the efforts to stop (extremist content) being uploaded in the first place."
"Terrorist groups are aware that links to their propaganda are being removed more quickly, and are placing a greater emphasis on disseminating content at speed in order to stay ahead," May, a former interior minister, said.
"Industry needs to go further and faster in automating the detection and removal of terrorist content online, and developing technological solutions which prevent it being uploaded in the first place."
EU threatens legislation
The EU has threatened legislation if internet companies do not better police what is available on the web.
French President Emmanuel Macron and Italian Prime Minister Paolo Gentiloni said in New York also on Wednesday that content must be removed swiftly. "This is what must be done. In one hour the content must be identified, analyzed and withdrawn to avoid it being broadcast widely. Experience shows that this is possible,” said Macron.
"Every hour counts, every moment, because young people and older have access to this propaganda and can "flip" into a very serious fragile situation," Macron said.
Macron proposed a "name and shame" policy for companies that don't fall into line with the plans. "We have to praise those who want to go with us and denounce those who are against us," he said.
"Because in the terrorist battle there are only two sides - those who fight for our values, our freedoms, the lives of our citizens and there are those who decide to go with the terrorists," Macron added.
"You have to decide where you stand. Ambiguity is no good here."
Meanwhile, Gentiloni said economic and privacy issues were a hurdle in this process, "but we also have to know, if we are aware of the fact that this battlefield is so relevant, that we can't reduce our ambition because of the difficulties."
"We have a real battlefield for hearts and minds and (it) is the web," he said.
A scientific challenge
Kent Walker, general counsel for Alphabet Inc's Google said removing all such content within a few hours - or indeed stopping it from appearing on the internet in the first place - posed an enormous technological and scientific challenge.
"The haystacks here are unimaginably large and the needles are both very small and constantly changing," said Walker.
Walker was speaking on behalf of Facebook, Microsoft Corp, Google subsidiary YouTube and Twitter, all members of the Global Internet Forum to Counter Terrorism created in June.
Walker said that between August 2015 and June 2017, Twitter suspended almost a million accounts for the promotion of terrorism, and that the use of technology and artificial intelligence had allowed Facebook to root out "terrorist clusters."
Online retailer Amazon.com said on Wednesday it was reviewing its website after an investigation found it could help users buy the ingredients to make a bomb using its "Frequently bought together" and "Customers who bought this also bought" features.
jbh/rc (Reuters, dpa)