Facebook Inc. is taking one of President Donald Trump’s biggest megaphones away, possibly for good.

The social media giant took the unprecedented step Thursday of extending a block on Trump’s Facebook and Instagram accounts that it had put in place a day earlier, following a similar move by Twitter Inc., after he praised an angry mob of supporters who violently stormed the U.S. Capitol as Congress met to certify Joe Biden’s election as the next president. "We believe the risks of allowing the President to continue to use our service during this period are simply too great,” Chief Executive Officer Mark Zuckerberg said in a Facebook post. The block will last at least until Jan. 20, when Biden is sworn in.

After years of fitful action on questionable content, both Facebook and Twitter have struggled in recent months to take a harder stance over Trump’s often inflammatory posts. It started in May, when Twitter took the unheralded step of obscuring one of the president’s posts about protests over George Floyd’s death in Minneapolis — which included the comment "when the looting starts, the shooting starts” — saying it glorified violence. It also added fact-check notices to Trump tweets about mail-in voting. At the time, Facebook defended leaving up some controversial posts, with Zuckerberg famously saying his company should not "be the arbiter of truth of everything that people say online.” Going into the election, they both were more aggressive in adding fact-checking labels on misinformation promulgated by Trump and others. But it looks like it wasn’t enough.