Facebook ruled out a cyber attack speculation which started making the rounds when products of its family of apps — WhatsApp, Instagram and Messenger — began encountering service outage for nearly eight hours in what appeared to be one of the longest downtimes.

On Wednesday, users across the globe experienced problems sending messages on Messenger and Whatsapp. The social networking giant's photo-messaging app Instagram also suffered service disruptions.

After users reported about the inconvenience faced by them on the websites and mobile apps, Facebook took to Twitter to respond: "We're aware that some people are currently having trouble accessing the Facebook family of apps. We're working to resolve the issue as soon as possible."

The tech major confirmed that the problem was not related to a Distributed Denial of Service (DDoS) cyber attack.

"We're focused on working to resolve the issue as soon as possible, but can confirm that the issue is not related to a DDoS attack," Facebook informed the users, who believed the service disruption could be a "cyber attack".

Although the users could open Facebook and Instagram mobile apps, they experienced troubles uploading posts, say reports.

"We're aware of an issue impacting people's access to Instagram right now. We know this is frustrating, and our team is hard at work to resolve this ASAP," Instagram tweeted.

Earlier in the day, WhatsApp appeared to be fine for many people, but users in India, Bangladesh, Argentina, and more noticed issues with sending messages as the afternoon went on. Users in Brazil were experiencing the most severe outages, The Verge reported.

Users also noted that attempting to use Facebook to sign into apps like Tinder or Spotify was not working either.

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Internet users made their way to Twitter to complain about the hours-long service disruption with hashtags such as "#FacebookDown", "#InstagramDown" and "#Whatsapp".

Also on Wednesday, Google and its services including Gmail, Maps and Drive went down globally. (IANS)