A group of WikiLeaks supporters is taking aim at the web sites of governments opposed to the information-sharing site.
Experts say that the group has begun to launch distributed denial of service (DDoS) attacks on government sites including that of Tunisia.
Sophos senior technology consultant Graham Cluley said in a blog post that the attacks appear to be part of an ongoing campaign against governments that have tried to block access to WikiLeaks.
The researcher noted a similar attack recently launched against the government of Zimbabwe.
The group behind the attack bills itself as an operation of the Anonymous internet movement. Similar groups have previously been linked to DDoS attacks on WikiLeaks opponents such as PayPal and MasterCard.
WikiLeaks, meanwhile, has denied any affiliation with the Anonymous movement or contact with those behind it.
The site has found itself under attack from the government and private sector in recent weeks after posting a collection of leaked cable transmissions.
Meanwhile, Wikileaks founder Julian Assange was accused of sexual assault in Sweden. Assange has denied the charges and dismissed the case as a political attack.