Facebook blocks a million messages every week that promote terrorism or radical ideologies, said executive director of UN Counter-Terrorism Committee Jean-Paul Laborde.
"We must learn to move through social networks at the same speed or faster than terrorist organisations," Efe quoted Laborde as saying on Thursday.
He said this while addressing a meeting on balance between protecting citizens and maintaining their online privacy, which according to Laborde is "a great challenge" for law enforcement, civil society and private companies.
"We must find the balance between ensuring freedom and privacy online, but at the same time it is necessary to protect the lives of all citizens of the world," said Laborde.
"One area in which we must first defeat terrorist organisations such as Islamic State is the internet and social networks," he added.
To achieve these goals new relationships and connections must be forged between civil society, UN members and private enterprises like Facebook, Google, Microsoft and Twitter that control exchange of information online.
"Private companies do not want to look like the bad guy and are doing much to help," said Laborde and added YouTube cancelled at least 14 million videos of terrorist propaganda in the last two years.