SYDNEY, March 19 (Reuters) - An Australian regulator has

sent legal letters to social media platforms from YouTube, X and

Facebook to Telegram and Reddit, demanding they hand over

information about their efforts to stamp out terrorism content.

The e-Safety Commission said it was concerned the platforms

were not doing enough to stop extremists from using

live-streaming features, algorithms and recommendation systems

to recruit users.

Since 2022, the regulator has had the power to demand big

tech firms give information about the prevalence of illegal

content and their measures to prevent that content from

spreading. Failure to do so can result in hefty fines.

Inman Grant said Telegram was the most used by violent

extremist groups to radicalise and recruit.

The Dubai-based messaging service, which a 2022 OECD report

ranked at No. 1 for frequency of terrorism content, did not

immediately respond to a Reuters request for comment.

"We don't know if they actually have the people and

resources in place to even be able to respond to these notices,

but we will see," Commissioner Julie Inman Grant told Reuters in

an interview.

"We're not going to be afraid to take it as far as we need

to, to get the answers we need or to find them out of compliance

and fine them," she added.

She also said that second-ranked YouTube "has the power

through their clever algorithms to spread propaganda broadly ...

in a very overt way or a very subtle way that sends people down

rabbit holes."

Subjects considered terrorism ranged from responses to the

wars in Ukraine and Gaza to violent conspiracy theories to

"misogynistic tropes that spill over into real-world violence

against women", she added.

The regulator has previously sent legal letters to platforms

seeking information about the handling of child abuse material

and hate speech, but its anti-terrorism blitz has been the most

complex because of the wide range of content and methods of

amplifying content, Inman Grant said.

Elon Musk's X was handed the first e-Safety fine in 2023

over its response to questions about its handling of child abuse

content. It is challenging the $386,000 fine in the court.

The commission targeted Telegram and chat forum website

Reddit for the first time in this round of legal

letters which were sent on Monday. A white supremacist who

killed 10 Black people in Buffalo, New York in 2022, has said

the platform contributed to his radicalisation.

Reddit, X and YouTube owner Alphabet were not

immediately available for comment.

A spokesperson for Facebook owner Meta said the

company was reviewing the commission's notices and that "there

is no place on our platforms for terrorism, extremism, or any

promotion of violence or hate".