The despicable video of a gunman's rampage through two New Zealand mosques was seen by millions of people, thanks to the rapid proliferation on platforms like Facebook, Google and Twitter.

Since the incident, the backlash against Big Tech has grown as the Silicon Valley mainstays have struggled to explain how and why the horrible video was able to spread so easily and quickly.

On Tuesday, New Zealand's three main telecommunication companies, Spark, Vodafone NZ and 2degrees, released a scathing letter to the CEOs of the world's largest tech platforms demanding more action to remove such content in advance as opposed to being reactive.

FACEBOOK UNDER FIRE AS WATCHDOG GROUP DISPUTES CLAIM NEW ZEALAND MASSACRE VIDEO WAS NOT FLAGGED

"We call on Facebook, Google and Twitter, whose platforms carry so much content, to be a part of an urgent discussion at an industry and New Zealand government level on an enduring solution to this issue," the letter, which was posted on the companies websites, reads.

YouTube announced that its artificial intelligence software didn't work as well as it had hoped. Facebook, which said it removed 1.5 million videos in the first 24 hours after the attack (1.2 million before they were seen by users), also struggled to address the spread of the New Zealand video.

"Although we recognize the speed with which social network companies sought to remove Friday's video once they were made aware of it, this was still a response to material that was rapidly spreading globally and should never have been made available online," the telecoms' statement says. "We believe society has the right to expect companies such as yours to take more responsibility for the content on their platforms."

YOUTUBE STRUGGLED TO REMOVE NEW ZEALAND SHOOTING VIDEOS. THIS IS WHY

The three telecom companies took the unprecedented step in the afternoon of the attack to jointly identify and suspend access to websites that were hosting video footage recorded by the alleged gunman as he mowed down worshipers at two mosques in Christchurch.

"We believed this extraordinary step was the right thing to do in such extreme and tragic circumstances," the telecom companies said. "More needs to be done to prevent horrific content from being uploaded. Already there are AI techniques that we believe can be used to identify content such as this video, in the same way that copyright infringements can be identified. This must be prioritized as a matter of urgency."

CLICK HERE FOR THE FOX NEWS APP

Besides the live-streamed video of the attack itself, the suspected gunman and self-identified white supremacist also reportedly uploaded a 74-page manifesto that detailed his plans and railed against Muslims and immigrants.

Fox News has reached out to Facebook, Google and Twitter for comment.