The internet is down in Syria, and mobile phone service has been disrupted, as rebels continue to clash with government forces.
Aall 84 of Syria's IP address blocks have become unreachable, says monitoring form Renesys, effectively removing the country from the internet altogether.
Even five smaller netblocks originating from Tata Communications offshore were brought down some time after the rest.
The Syrian government - rather implausibly, to say the least - is claiming that the outage is caused by terrorists.
"Looking back over the last week, you can see that the routing of the Syrian internet has actually been pretty stable until today's wholesale shutdown," says Renesys' James Cowie.
"There have been some brief up-and-down flickers affecting the reachability of a particular 12 networks, and there was one brief whole-country outage of less than ten minutes on 25 November. By the time that one was confirmed, the outage was over."
It may have been some sort of practice run, he suggests.
Google's noticed the effects of the blackout too, saying that all its services - including YouTube, beloved of dissidents worldwide - were down as of yesterday. When a similar backout occurred in Egypt, the company introduced a 'speak-to-tweet' service which allowed people to connect to Twitter via the phone; there's no word yet on whether it plans to do the same in Syria.
"Syria's internet shutdown underscores the continuing threat that governments pose to an open internet, especially in countries where the government has direct control over the backbone," say Eva Galperin and Jillian York of the Electronic Frontier Foundation.
"As fighting intensifies, particularly around Damascus, we are extremely worried that the news that internet and mobile phone services appear to have been cut throughout Syria may herald the intention of the Syrian authorities to shield the truth of what is happening in the country from the outside world," adds Amnesty International Middle East and North Africa deputy director Ann Harrison.