CloudFlare writes how Syria likely disconnected itself from the internet. Contrary to some published statements about lines being cut, it seems as if it was designed.

While we cannot know for sure, our network team estimates that Syria likely has a small number of edge routers. All the edge routers are controlled by Syrian Telecommunications. The systematic way in which routes were withdrawn suggests that this was done through updates in router configurations, not through a physical failure or cable cut.

They even produced a video showing how the routes were organized and eliminated.

via by way of James Duncan Davidson