Apologizing for the disruption in the services of Facebook, Whatsapp, and Instagram, tech giant’s CEO Mark Zuckerberg has stated that services are returning online on Tuesday.

“Facebook, Instagram, WhatsApp, and Messenger are coming back online now,” Zuckerberg said in a Facebook post. “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.

Taking to Twitter early on Tuesday, WhatsApp said: “Apologies to everyone who hasn’t been able to use WhatsApp today. We’re starting to slowly and carefully get WhatsApp working again. Thank you so much for your patience. We will continue to keep you updated when we have more information to share.”

Users started reporting that Instagram, WhatsApp, and other services under the Facebook corporate umbrella are now accessible as normal for the first time since about 11:30 EST on Monday when reports of the outage and disrupted services began pouring in, according to Sputnik.

Earlier, a site that monitors reports of outages across the internet, Downdetector, said the Facebook service outage is the largest it has ever seen.

The company said in a post on Monday, “The largest outage we’ve ever seen on Downdetector with over 10.6 million problem reports from all over the globe.

“The US-led the world in the number of reports for disrupted service of more than 1.7 million, followed by Germany at 1.3 million reports and the Netherlands at 9,15,000 reports.

Monday’s outage has left several services under the Facebook corporate umbrella, including Instagram, WhatsApp, and Messenger, inaccessible.

Meanwhile, Telegram said on Twitter that users of its messenger in some regions, amid large-scale outages on Facebook, may experience problems loading chats and receiving notifications. It said the company apologizes for the inconvenience.