The head of Ukraine's presidential administration, Dmytro Shymkiv, told the Financial Times that his country's government warned Facebook and U.S. officials in 2015 that Russia was using "aggressive behavior" to spread disinformation on social media in an "information war." Shymkiv said Facebook's response was that they're an "open platform" that allows everyone to communicate.

Why it matters: The Ukrainian assertions suggest that Russian fake news was detected much earlier than the tech giants have so far let on. Axios reported yesterday that a former FBI agent had detected Russia's use of fake news and automated bots in 2014. The investigation into Russia's interference in the 2016 election and big tech's role has come to a head this week with interrogations of Google, Twitter and Facebook by both the House and Senate Intelligence Committees.

Facebook's defense: