(Adds comments from British officials, details)
SINGAPORE, March 15 (Reuters) - Social media giants Facebook, Twitter, Google faced scrutiny over extremist content on their platforms on Friday after video footage of mass shootings in New Zealand was live streamed and widely shared online.
Footage of the attacks at two mosques, which left 49 dead in New Zealand's worst-ever mass shooting, was broadcast live to Facebook and then reshared by users on other platforms.
Following the shootings, Facebook, Twitter and YouTube all said they were taking action to remove the videos.
"Police alerted us to a video on Facebook shortly after the livestream commenced and we quickly removed both the shooter's Facebook and Instagram accounts and the video," Facebook tweeted.
"We're also removing any praise or support for the crime and the shooter or shooters as soon as we're aware."
Twitter said it had "rigorous processes and a dedicated team in place for managing exigent and emergency situations" such as this. "We also cooperate with law enforcement to facilitate their investigations as required," it said.
Alphabet Inc's YouTube said: "Please know we are working vigilantly to remove any violent footage."
But hours after the attack, copies of the footage were still available on Facebook, Twitter, YouTube, as well as Facebook-owned Instagram and WhatsApp.
The videos show the gunman driving to one mosque, entering it and shooting randomly at people inside. Reuters was unable to confirm the authenticity of the footage.
Britain's interior minister said the companies needed to take more action.
"You really need to do more @YouTube @Google @facebook @Twitter to stop violent extremism being promoted on your platforms," minister Sajid Javid wrote on Twitter. "Take some ownership. Enough is enough."
Live streaming services have become a central component of social media companies' growth strategy in recent years, but they are also increasingly exploited by some users to livestream offensive and violent content.
In 2017, a father in Thailand broadcast himself killing his daughter on Facebook Live. After more than a day, and 370,000 views, Facebook removed the video. That year, a video of a man shooting and killing another in Cleveland also shocked viewers.
(Reporting by Arjun Panchadar; Writing by Miyoung Kim and Jack Stubbs; Editing by Nick Macfie and Toby Chopra)
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