"Facebook, Instagram, WhatsApp and Messenger are coming back online now," Zuckerberg said on Facebook.
"Sorry for the disruption today -- I know how much you rely on our services to stay connected with the people you care about," he said.
The outage, which began around 11:30 EST, impacted Facebook, Instagram and Whatsapp users worldwide. The users of some other messengers, including Telegram, and services, were also affected.
Former Washington Post journalist Brian Krebs said on Twitter citing a member of Facebook's recovery team that the social networking service's outage was caused by a border gateway protocol (BGP) update.