Facebook on Friday set its ban on former US president Donald Trump for two years, saying he deserved the maximum punishment for violating platform rules over a deadly attack by his supporters on the US Capitol.

The two-year ban will be effective from January 7, when Trump was booted off the social media giant, and comes after Facebook's independent oversight board said the indefinite ban imposed initially should be reviewed.

"Given the gravity of the circumstances that led to Mr. Trump's suspension, we believe his actions constituted a severe violation of our rules which merit the highest penalty available under the new enforcement protocols," Facebook vice president of global affairs Nick Clegg said in a post.

In updating its policies, Facebook also said it will no longer give politicians blanket immunity for deceptive or abusive content at the social network based on their comments being newsworthy.

At the end of Trump's two-year ban, Facebook will enlist experts to assess whether his activity at the social network still threatens public safety, according to Clegg.

"If we determine that there is still a serious risk to public safety, we will extend the restriction for a set period of time and continue to re-evaluate until that risk has receded," Clegg said.

When Trump's suspension is lifted, he will face strict sanctions that could rapidly escalate to permanent removal from the social network for rule-breaking, according to Clegg.

Last month, the independent oversight board said Facebook was justified to oust Trump for his comments regarding the deadly January 6 rampage at the US Capitol but that the platform should not have applied an "indeterminate and standardless penalty of indefinite suspension."

Trump denounces 'insult'

Trump said in a statement the ban was an "insult" to voters, renewing his false claims that the 2020 presidential election was stolen from him.

"They shouldn't be allowed to get away with this censoring and silencing," Trump said.

Trump also took a jab at Facebook founder Mark Zuckerberg, who attended a White House dinner with the former president in 2019.

"Next time I’m in the White House there will be no more dinners, at his request, with Mark Zuckerberg and his wife," Trump said. "It will be all business!"

Some activists criticized Facebook for even opening the door to reinstating Trump.

Angelo Carusone of the left-leaning watchdog group Media Matters for America, called Facebook's move dangerous, saying that if Trump is reinstated, "the platform will remain a simmering cauldron of extremism, disinformation, and violence."

Activists joined together in a group that calls itself The Real Facebook Oversight Board said: "Facebook shouldn’t have needed a $130 million Oversight Board and a team of law professors to tell them dictators and authoritarians were running wild on their platform."

White House press secretary Jen Psaki, when asked about the Facebook decision, said that a social platform that is disseminating information to millions of Americans, "has a responsibility to crack down on disinformation... whether it's about the election or even about the vaccine."

Trump was suspended from Facebook and Instagram after posting a video during the attack by his fired-up supporters challenging his election loss, in which he told them: "We love you, you're very special."

The oversight panel called on Facebook to justify why his ban should be permanent -- sending the matter back to Zuckerberg, who has long argued that private companies should not be the arbiters of truth online.

The oversight board, which was created as part of Zuckerberg's vision for a "supreme court" for difficult content decisions, said it will comment after reviewing Facebook's announcement.

Immunity revoked

As part of its new policy, Facebook will step back from its "newsworthiness" exception which allowed false information from Trump and others to circulate.

Facebook will begin publishing the "rare instances" in which offending posts are tolerated, and will not treat content posted by politicians differently from content posted by anyone else, according to Clegg.

New York University Stern Center deputy director Paul Barrett welcomed the move by Facebook.

"Donald Trump illustrated how a political leader can abuse social media to undermine democratic institutions such as elections and the peaceful transfer of power," Barrett said.

"Facebook was justified in removing Trump from its platforms, and now the company has appropriately decided to enforce its rules more vigorously against other political figures, as well."

Knight First Amendment Institute executive director Jameel Jaffer was troubled by Facebook putting all the blame for disinformation on users, and urged a study of how the design of the leading social network may be a factor in its spread.