WASHINGTON • Under-fire Facebook said it was turning over more than 3,000 Russia-linked ads to congressional committees probing the Kremlin's meddling during last year's US presidential campaign.
"I care deeply about the democratic process and protecting its integrity," Facebook's chief executive Mark Zuckerberg said on Facebook Live, the company's video service. He added that he did not want anyone "to use our tools to undermine democracy".
Thursday's announcement that Facebook would share the ads with the Senate and House intelligence committees came after the social network spent two weeks on the defensive.
The company faced calls for greater transparency about 470 Russia-linked accounts, in which fictional people posed as United States activists, which were taken down after they promoted inflammatory messages on divisive issues.
Facebook previously angered congressional officials by showing only a sample of the ads, some of which attacked Mrs Hillary Clinton or praised Mr Donald Trump.
Facebook's admission earlier this month that Russian agents covertly bought ads on the site has led to intense scrutiny of the social network and Twitter, entangling both companies in the probe by special counsel Robert Mueller.
The disclosure of the ads also raised the possibility of future regulation of political advertising on social media.
For Facebook, the move to work with the congressional committees underscored how far it has strayed from being a mere technology company and how it has increasingly had to deal with the unintended consequences of the tools it provides to reach the more than two billion regular users of its site.
I care deeply about the democratic process and protecting its integrity. (I do not want anyone) to use our tools to undermine democracy.
FACEBOOK'S CHIEF EXECUTIVE MARK ZUCKERBERG, who posted his statement on the firm's video service.
The company became more proactive in deflecting criticism this week, with chief operating officer Sheryl Sandberg describing on Wednesday the steps it would take to strengthen its ad system.
On Thursday, in a move clearly intended to pre-empt government intervention, Mr Zuckerberg outlined the list of actions Facebook planned to take in the coming weeks to make political advertising more transparent.
He said each advertisement would show which Facebook Page - a kind of account required for businesses to create an ad - had paid for the ad, although that would not necessarily identify the people behind the Facebook Page.
In addition, Facebook plans to invest more heavily in its security teams, expand its coordination with global election commissions and work closely with other tech companies to share threat information as it arises.
Twitter, which has kept a low profile since Facebook's disclosure of the Russian intrusion, has announced that it will brief the Senate Intelligence Committee on Wednesday in private.
Senator Mark Warner, the top Democrat on the intelligence committee, called Facebook's announcement " a good first step".
He added: "I'm disappointed it's taken 10 months of raising this issue before they've become much more transparent."