Following the attack by supporters of President Donald Trump against the US Capitol on January 6, the social media company said it will now prohibit ads for accessories such as gun safes, vests and gun holsters in the United States.

"We already prohibit ads for weapons, ammunition and weapon enhancements like silencers. But we will now also prohibit ads for accessories," Facebook said in a blog post.

Three US senators sent a letter to Facebook Chief Executive Mark Zuckerberg on Friday asking him to permanently block ads for products that are clearly designed to be used in armed combat.

The senators, all Democrats, said the company must take this and other actions to "hold itself accountable for how domestic enemies of the United States have used the company's products and platform to further their own illicit aims."

Facebook on Friday blocked the creation of any new Facebook events in close proximity to places such as the White House and US Capitol in Washington, as well as state capitol buildings, through January 20.

The FBI has warned of armed protests being planned for Washington and all 50 state capitals in the run-up to the inauguration.

Buzzfeed reported this week that Facebook had been running ads for military equipment next to content promoting election misinformation and news about the Capitol violence.

A Facebook company spokesperson said all the pages identified in the Buzzfeed story had been removed.

Australian Associated Press