The hackers, who apparently gained access to the site's server from Germany, posted photos of dead Chechen militants, Emir Ibn al Khattab and Shamil Basayev.
The spokesman said the attack was aimed "at discrediting the republic's government and the youth policy it is carrying out."
Jordanian-born Khattab was killed in March 2002 in an operation carried out by Russia's Federal Security Service (FSB). The notorious Chechen militant Basayev was killed by Russian troops in July 2006.
According to initial reports the hackers are believed to be from Moscow. The website, which was launched in 2005, is very popular with young people.
The site is currently out of action while computer technicians repair the damage.
Although the active phase of the antiterrorism campaign in the North Caucasus officially ended in 2001, periodic bombings and clashes between militants and federal troops still disrupt Chechnya and nearby regions, including Daghestan and Ingushetia.
