The New York Times' website went down for several hours on Tuesday and some users were still having problems Wednesday after it was hit with a "malicious external attack."
A tweet from the official Times Twitter account was directing readers to an alternative website -- http://news.nytco.com -- if they were having difficulties accessing the main site at nytimes.com. Readers in Europe and Asia were reporting problems Wednesday.
Marc Frons, chief information officer at the Times, told employees Tuesday that the outage was the result of an attack on Melbourne IT, the company's domain name registrar, according to the New York Times.
Frons told the Times that the hacktivist group Syrian Electronic Army was responsible for the attack -- "or someone trying very hard to be them." The Syrian Electronic Army is a group of hackers aligned with Syrian President Bashar al-Assad.
The group sent a tweet claiming responsibility for the Times attack, and SEA also claimed that it took over Twitter's own domain on Tuesday afternoon.
The Federal Bureau of Investigation has begun looking into the website disruption, a law enforcement official told CNN. The "preliminary inquiry" is still in its early stages, the official said.
The Times did not reply to a request for comment.
Two weeks ago, Syrian Electronic Army claimed responsibility for hacking Outbrain, a news recommendation engine that appears on websites including The Washington Post , CNN and Time. The hacked news links were redirecting to a site controlled by the hacking group, which supports Syrian President Bashar al-Assad and has taken credit for several recent cyberattacks.
The New York Times' own website had suffered an outage the day before the Outbrain hack, prompting speculation that hackers were responsible, but a spokeswoman for the paper said that outage was the result of complications associated with a scheduled maintenance update.
--CNNMoney's Alanna Petroff and CNN's Evan Perez contributed to this report.