A pro-Assad group of hackivists is threatening attacks on Western media outlets.
The so-called Syrian Electronic Army is suspected of being responsible for hacking the New York Times website.
The newspaper said the website was the subject of "a malicious external attack" earlier, which made it unavailable to many users.
A Twitter account claiming to represent a hacktivist group called the Electronic Syrian Army tonight posted the words "media is going down" - referring to the New York Times, and the Huffington Post.
It also claimed that Twitter in the UK had been brought down.
