Facebook's quasi-independent Oversight Board is set to announce Wednesday whether the social media company was correct to indefinitely prohibit former U.S. President Donald Trump from posting to his Facebook and Instagram accounts.

The board is made up of 20 members, including legal scholars, human rights experts and journalists. A panel of five members prepares a decision, which must be approved by a majority of the full board, and which Facebook is then required to implement unless the action could violate the law.

The board says its mission is to "answer some of the most difficult questions around freedom of expression online: what to take down, what to leave up, and why."

Trump's ban dates to the January 6 attack on the U.S. Capitol by his supporters that came as members of Congress were meeting to certify the results of the November presidential election.

In this Jan. 6, 2021, file photo, Trump supporters participate in a rally in Washington.

He made several posts during the attack continuing his false claims that the election was "stolen." Facebook removed two of Trump's posts and initially banned him from posting for 24 hours.

"These are the things and events that happen when a sacred landslide election victory is so unceremoniously viciously stripped away from great patriots who have been badly unfairly treated for so long," Trump posted about two hours before police and National Guard troops secured the Capitol. "Go home with love in peace. Remember this day forever!"

Facebook decided the next day to extend Trump's ban indefinitely, at least past the inauguration of President Joe Biden.

"His decision to use his platform to condone rather than condemn the actions of his supporters at the Capitol building has rightly disturbed people in the US and around the world. We removed these statements yesterday because we judged that their effect -- and likely their intent -- would be to provoke further violence," Facebook CEO Mark Zuckerberg said in a January 7 statement.

Twitter instituted a permanent ban against Trump, saying several of his posts "are likely to inspire others to replicate the violent acts that took place on January 6, 2021, and that there are multiple indicators that they are being received and understood as encouragement to do so."

The Facebook Oversight Board was created last October after the company faced criticism it was not quickly and effectively dealing with what some feel is problematic content.

The board announced its first decisions in January, supporting Facebook's decision to remove content in one case, but overruling the company and ordering it to restore posts in four other cases.