In the past, Turkey has done similar, censoring tweets and condemning social media as "the worst menace to society." Late last year, Congo ordered cuts to the internet and SMS to slow down protesters. And less than a day after that instance, Iranian officials blocked mobile access to Instagram and Telegram. Unfortunately, these reports of free speech being squashed by the local government continue to surface on a regular basis.
We've reached out to the affected companies for more information and will update this post should it arrive.
Update: A Facebook spokesperson responded with the following comment, which applies to Instagram as well:
"The safety of our community is absolutely critical to us. We have clear rules against hate speech and incitement to violence and work hard to keep it off our platform. We are responding to the situation in Sri Lanka and are in contact with the government and non-governmental organizations to support efforts to identify and remove such content."