Facebook has turned over to Russia special counsel Robert Mueller more specific information about Moscow ad purchases than it did to congressional investigators last week, The Wall Street Journal reported Friday.
The Journal based its report on "people familiar with the matter."
The information provided to Mueller's investigators include "copies of the ads and details about the accounts that bought them and the targeting criteria they used," the Journal reported.
Facebook policy normally requires the company to disclose "the stored contents of any account," including messages and location information in a search warrant request, according to the report.
The social networking site, based in Menlo Park, Calif., has not shared such detailed information with Congress, "in part because of concerns about disrupting the Mueller probe, and possibly running afoul of U.S. privacy laws," the Journal reported.
A Facebook spokesman told the newspaper that the company was continuing its probe and was cooperating with federal authorities.
A Mueller spokesman declined to comment.
Facebook disclosed last week that it had identified about 500 "inauthentic" accounts with Russian ties that purchased $100,000 in ads over two years, which included the time during the presidential campaign.
In addition, the company also found $50,000 in ad purchases linked to Russian accounts.
Those funds bought more than 5,000 ads on Facebook, the company said.
Last week's disclosure was Facebook's first acknowledgment that Russians had used the company to reach Americans during the presidential campaign.
The announcement came about two months after Facebook said it had no evidence of Russian ad purchases.
Russia has denied any involvement in the election — and President Donald Trump slammed the Mueller probe as a "witch hunt."
Sen. Mark Warner, the Virginia Democrat who co-chairs the Senate Intelligence Committee, said last week that Twitter officials would soon talk with congressional investigators about Russian activity on its platform, the Journal reported.
A Twitter spokeswoman declined to comment.
In a statement, Google told the Journal: "We're always monitoring for abuse or violations of our policies and we've seen no evidence this type of ad campaign was run on our platforms."
The company has not been called to testify in the Russia probe, the Journal reported.