"From 3:35 UTC today, approximately two thirds of all networks of Syria became unreachable from the global Internet," said Renesys Internet intelligence firm in his blog today.
"Over half an hour, the routes to 40 of 59 networks were withdrawn from the global routing table."
Most mobile phones and Internet networks are affected by the blackout. According to The Wall Street Journal, Web sites run by government, such as the website of the Ministry of Petroleum is still running.
Syria has been the prohibition of social media services in recent months, but this is the full time has been cut all to the Internet.
The decision comes as protests have intensified in the troubled nation. 34 people were killed on Friday after security forces opened fire. The uprising, which began in late January, has focused on the dismissal, Bashar Al-Assad and his role as President of Syria. Al-Assad became president in 2000 after 29-year rule of his father.
Former Egyptian President Hosni Mubarak, close Internet services during the Egyptian revolution protesters were not easy to organize. Do not put down the revolt, however, and on February 11, Mubarak resigned.