Tech companies are sharing more information with law enforcement in a frantic effort to prevent violence around the inauguration, after the government was caught flat-footed by the Capitol siege.

Between the lines: Tech knows it will be held accountable for any further violence that turns out to have been planned online if it doesn't act to stop it.

Driving the news: Facebook on Friday announced new measures aimed at preventing people from using its platform to foment violence.

• The company is blocking the creation of new Facebook events in locations close to the White House, U.S. Capitol and state capitol buildings through Inauguration Day.
• It's also reviewing events related to the inauguration and removing those that violate policies.
• And it's restricting U.S. accounts that have repeatedly violated Facebook policies from creating live videos or events, Groups or Pages.

What we're hearing: Some companies, including Facebook and Twitter, have briefed the Hill on recent talks they've had with law enforcement.

• The companies are sharing information about troubling material they find on their platforms as well as soliciting threat information from law enforcement so they can act against problematic accounts.
• Facebook also meets regularly with other tech firms to warn each other about security threats they detect on their platforms, said a Facebook source.

What they're saying: "We are continuing our ongoing, proactive outreach to law enforcement and have worked to quickly provide responses to valid legal requests," a Facebook spokesperson told Axios.

• "We are removing content, disabling accounts, and working with law enforcement to protect against direct threats to public safety."
• A Twitter spokesperson said the company is "working closely with law enforcement and federal government partners, including the FBI, [the Department of Homeland Security], and others to help mitigate potential risks."
• The company also says it's expediting law enforcement requests.

Our thought bubble: It remains to be seen whether measures like blocking Facebook events still make a difference in thwarting threats. Many bad actors are moving to less visible platforms and may be unlikely to plan another attack out in the open.

And Facebook's ads aren't exactly reinforcing the message of preventing violence. It has run ads for military equipment, including body armor and gun holsters, next to news about the Capitol attack, according to a Buzzfeed report.

• Facebook does not allow ads for guns, ammo or explosives, but its policies permit tactical gear to be advertised to users aged 18 and older. 

Catch up quick: Other companies have rolled out changes since the Capitol siege to prevent their platforms from being used for a repeat on Inauguration Day.

• Airbnb said Wednesday it is canceling existing reservations and blocking new ones in and around Washington, D.C., during inauguration week as federal officials remain on alert for potential violence.
• Twitter has suspended more than 70,000 accounts for sharing QAnon content, and it has blocked keywords from its search and trending features that break its rules related to civic integrity and glorification of violence.
• Google told advertising partners Wednesday that beginning Jan. 14, its platforms will block all political ads, as well as any related to the Capitol insurrection. A limited version of its "sensitive event" policies went into effect after the Capitol attack to help curb ads that could be used to sow confusion, or help lead people to materials that could be used in protests, like mace.
• Snapchat decided to permanently ban President Trump, citing risks to public safety, Sara scooped Wednesday night.