Facebook thought about disclosing election manipulation by Russia in April, but waited until September

Facebook omitted references to Russia in a public report published in April about manipulation on the site during the 2016 election, according to a new Wall Street Journal report.

The company eventually disclosed in September that it had found about 3,000 ads from Russia-linked fake accounts. Those ads were viewed by about 10 million people, the company said. There may still be more Russia-linked abuse on Facebook that hasn't been discovered yet.

A Facebook spokesperson told the WSJ that the company didn't disclose the Russia-linked activity in April because the company was still looking into the matter. The 3,000 ads weren't discovered until after the April report.

Facebook said last month that it would soon require more transparency from political ads. The company also said it would hire 1,000 more people to monitor ads for abuse.