Facebook chief operating officer Sheryl Sandberg said Tuesday the company needs to step up its efforts to curb misinformation after research revealed that Russia-backed organizations targeted African-Americans, who favored Hillary Clinton, to suppress voter turnout during the 2016 election.

US intelligence agencies had earlier concluded that Russia interfered in the election to help President Trump by undermining Democratic candidate Clinton.

“Two independent reports commissioned by the Senate Select Committee on Intelligence released Monday on the Russian Internet Research Agency’s (IRA) use of technology around the 2016 election suggest that the IRA’s efforts had a disproportionate impact on communities of color,” Sandberg said in a blog post.

“We know that we need to do more: to listen, look deeper and take action to respect fundamental rights,” Sandberg said.