Internet traffic to and from Syria "disappeared" Tuesday, according to a site that tracks web traffic, dpa reported.
Traffic between Syria and Google's servers ceased around 2100 GMT, US-based Umbrella Security Labs said in a blog post Tuesday.
"It seems Syria has largely disappeared from the Internet," the company said on its Global Transparency blog. "OpenDNS resolvers saw a significant drop in traffic from Syria."
In the past the Syrian regime is believed to have cut internet ties on a regional basis in advance of major battles to disrupt rebel communications and prevent reports reaching the outside world.
Tuesday's shutdown effectively "disconnects Syria from Internet communication with the rest of the world," the company said.
The disruption comes at a time of mounting tension in the three-year-old civil war, just days after an Israeli air strike and amid allegations that both the regime and rebel fighters used chemical weapons.