Human rights groups raised concerns about hate speech on Twitter and the power that its takeover by Elon Musk would give the billionaire after the self-described "free speech absolutist" clinched a deal to take the social media platform private.
Musk, who is also chief executive of electric car maker Tesla, has been critical of Twitter's policies of moderating content on the platform.
He has said Twitter needs to become a genuine forum for free speech. In a statement after securing the deal on Monday, local time, Musk described free speech as "the bedrock of a functioning democracy".
Twitter is not just another company, human rights advocates noted.
"Regardless of who owns Twitter, the company has human rights responsibilities to respect the rights of people around the world who rely on the platform," Deborah Brown, a digital rights researcher and advocate at Human Rights Watch, told Reuters in an email.
"Changes to its policies, features, and algorithms, big and small, can have disproportionate and sometimes devastating impacts, including offline violence.
"Freedom of expression is not an absolute right, which is why Twitter needs to invest in efforts to keep its most vulnerable users safe on the platform," she added.
Twitter did not immediately respond to a request for comment on concerns raised by the groups.
"While Elon Musk is an ACLU card-carrying member and one of our most significant supporters, there’s a lot of danger having so much power in the hands of any one individual," Anthony Romero, executive director at the American Civil Liberties Union, told Reuters after the deal was announced.
Amnesty International said it was concerned about any potential decision that Twitter may take after Musk's takeover to erode enforcement of the policies and mechanisms designed to moderate hate speech online.
"The last thing we need is a Twitter that willfully turns a blind eye to violent and abusive speech against users, particularly those most disproportionately impacted, including women, non-binary persons, and others," Michael Kleinman, director of technology and human rights at Amnesty International USA, said.
Meanwhile Twitter CEO Parag Agrawal told employees that the future of the social media firm is uncertain after the deal to be taken private under billionaire Elon Musk closes.
He was speaking during a company-wide town hall meeting that was heard by Reuters.
Musk will join Twitter staff for a question-and-answer session at a later date, the company told employees.
As Agrawal listened to staff questions about Musk's plans for the company, the possibility of layoffs and the board's rationale for the deal, he deferred many questions as ones that should be asked of Musk.
Musk has said he believes Twitter should be a platform for free speech. Employees asked Agrawal whether former US President Donald Trump, who was permanently suspended from Twitter last year, would be allowed to return once Musk takes over.
"Once the deal closes, we don't know which direction the platform will go," Agrawal said, referring to the question regarding Trump. "I believe when we have an opportunity to speak with Elon, it's a question we should address with him."
That might not be an issue, however, with Trump himself saying he wouldn't return to the platform if he is reinstated.
The former US President told Fox News he was going to stay on his own Truth Social platform.
"I hope Elon buys Twitter because he’ll make improvements to it and he is a good man, but I am going to be staying on Truth," Trump said.
Agrawal also told employees there were no plans for layoffs.
Bret Taylor, chair of Twitter's board of directors, aimed to reassure employees that the agreement with Musk prioritised "operating continuity" until the deal was closed.
"I think we feel very comfortable that (the deal) gives this team the ability to continue to make the company successful in between signing and closing the transaction," Taylor said.