Facebook will share with U.S. congressional investigators some 3,000 political ads that it says Russia-based operatives ran on Facebook in the months before and after last year's U.S. presidential election.

"We believe it is vitally important that government authorities have the information they need to deliver to the public a full assessment of what happened in the 2016 election. That is an assessment that can be made only by investigators with access to classified intelligence and information from all relevant companies and industries - and we want to do our part. Congress is best placed to use the information we and others provide to inform the public comprehensively and completely," said Colin Stretch, General Counsel at Facebook.

Facebook asys that disclosing content is not something the social network typically does lightly under any circumstances. However, this particular investigation is related to the integrity of US elections.

"We believe the public deserves a full accounting of what happened in the 2016 election, and we've concluded that sharing the ads we've discovered, in a manner that is consistent with our obligations to protect user information, can help," Stretch added.

Chief Executive Mark Zuckerberg, who has been under pressure to do more to prevent the use of Facebook for election manipulation, first announced in a live broadcast on Facebook that he supported the investigation by the U.S. Congress.

Zuckerberg also laid out nine steps that he said Facebook was taking to deter governments from using the world's largest social network to interfere with elections.

In one major change, Facebook will make political ads on the social network more transparent, so that people can see which ads are being run in connection with an election, he said.