FORTUNE -- The New York Times' (nyt) Web site is entirely offline, along with its corporate site, leading to speculation that the newspaper of record has been hacked. The Times, though, has now said in a series of tweets that the problem is a "server issue" and "the result of an internal issue, which we expect to be resolved soon."
Earlier on Twitter, the Times cited "technical difficulties" but hadn't said anything else. Fox Business quoted a single unnamed "source close to the matter," saying the paper is the victim of a cyberattack. The Times' homepage reads "Http/1.1 Service Unavailable."
If there was indeed an attack on the Times' systems, it's not yet knowable where it came from.
In January, the paper reported that its computer systems were breached in a China-based attack. Passwords were stolen, the paper said, allowing intruders to access computers and email accounts over a four-month period. There were indications that the Chinese military was behind that attack, and that it might have been in response to a series the paper ran about the wealth of outgoing premier Wen Jiabao and his family.
The Times has taken to its Facebook page to post "key news articles" in their entirety.