The social network Parler has sued Amazon, arguing the ecommerce group’s decision to cut off web hosting services to the platform after the assault on the US Capitol by a mob supporting Donald Trump was illegal and violated antitrust laws.

The niche Twitter rival, which is popular among the far-right for its hands-off approach to content moderation, was forced offline on Sunday after Amazon withdrew its cloud services from the app, citing repeated failures to clamp down on violence-inciting content. Google and Apple banned the app from their stores over the weekend on the same grounds.

On Monday Parler filed a lawsuit in Amazon’s home state of Washington, alleging that the move by its Web Services division was “motivated by political animus” and “designed to reduce competition in the microblogging services market to the benefit of Twitter”.

The social network argued that Twitter, also a client of AWS, was losing market share to Parler as a result of its decision to permanently block the account of Mr Trump on Friday.

It comes as several tech groups, including Facebook and Airbnb, announced new, emergency policies ahead of the inauguration of president-elect Joe Biden on January 20, as fears grow that there could be a repeat of last week’s violence.

In a statement, AWS said the lawsuit, which included allegations of breach of contract, was “without merit”.

In a letter to Parler on Saturday, AWS had said its decision to cut off the app was motivated by repeated violations of its terms of service, and a lack, on the social network’s part, of any strategy for dealing with “a steady increase in violent content”.

“It’s clear that Parler does not have an effective process to comply with the AWS terms of service,” the letter read.

Moves by a handful of private Silicon Valley companies to “deplatform” the US president and his promotion machine have shone a spotlight on the political power that they now hold, reigniting debates around antitrust and free speech and embroiling them in the fallout from the US Capitol rampage.

Twitter’s share price fell 6.4 per cent on Monday to $48.18, as investors were spooked by the renewed debate into the prospect of tighter social media regulation.

The drop also reflected the end of the symbiotic relationship between the social media platform and Mr Trump, who obsessively used it to broadcast directly to his 88m followers, simultaneously attracting attention and users to the site.

Twitter also said that it had suspended 70,000 accounts since Friday as part of its efforts to cull promoters of the pro-Trump conspiracy cult QAnon “with many instances of a single individual operating numerous accounts”. In some cases the crackdown on the group, whose members were among those who attacked Capitol Hill, has reduced the follower count of certain Twitter users, it added.

While far smaller than rival Twitter, Parler, a self-described “unbiased social media network” that purports to champion “free speech”, had shot up app store rankings, receiving 9.6m installs globally in 2020, about 7.8m of which were in the US, according to data from SensorTower.

Despite a posting from Parler’s chief executive on Sunday suggesting the site had many options for alternative hosting and that it would be back online within a week, the court filing suggested that would not be possible.

“Parler has tried to find alternative companies to host it and they have fallen through. It has no other options. Without AWS, Parler is finished as it has no way to get online.”

Separately, Facebook on Monday announced a purge of all content related to “stop the steal” — a slogan referring to baseless allegations by Mr Trump and his supporters that the presidential election was stolen — from its platform.

It said the move was prompted by “continued attempts to organise events against the outcome of the US presidential election that can lead to violence, and use of the term by those involved in Wednesday’s violence in DC”, adding that the crackdown could take some time to fully enforce.

Sheryl Sandberg, Facebook’s chief operating officer, also said that the platform had no plans to lift its indefinite ban on Mr Trump. Some critics have urged the company to follow Twitter in making the suspension permanent.

Ahead of next week’s inauguration, the short-term rental site Airbnb said it would refer to police logs and ban those identified as being part of last week’s rioting, in addition to its existing measures designed to prevent known members of hate groups, such as the Proud Boys, from using its service.