Thousands of Israeli facebook users were infected by a virus Wednesday, days ahead of a planned cyber offensive against the Jewish State by international activists.

The purpose of the virus, which promulgates itself when a user clicks on certain notifications, is still not clear.

According to Mizbala, an agency specializing in specializing in guerrilla and experimental marketing, some 15% of users who clicked on the viral link were Israeli (14,500 as of Wednesday evening).

According to the Mizbala report (Hebrew) a user by the name of Bekir Yangeç was the source of the code. Mizbala offers its readers advice for action to be taken in the event they clicked on the link.

It isn’t clear if the virus does anything more than replicate and continue tagging, awaiting a user to click the link it provides.

The Facebook link virus appeared four days ahead of a threatened attack by hackers around the world who are plotting to strike Israel’s online presence in a coordinated cyber-strike later this week.

The effort, known as “OpIsrael,” which is being organized by hacktivist group Anonymous, aims to target the 100 largest websites in the country, especially those of banks, credit card companies, and communications firms.

The attack is scheduled to take place Sunday, April 7. That evening, Israel will begin to mark Holocaust Remembrance Day.

A hacker going by the name of “Mauritania Attacker,” who claims to lead a group of hackers called AnonGhost, said “the hacking teams have decided to unite against Israel as one entity, and Israel should be getting prepared to be ‘erased’ from the Internet.”

“Its gonna be the biggest ever operation launched against any country, Its gonna be Huge [sic]!” the activist told The Hackers Post.

Shai Blitzblau, CEO of Maglan Information Defense Technologies Research, told the Hebrew daily Israel Hayom Tuesday that the attackers’ skills are increasing all the time, but they have yet to break any new ground.

Experts have warned that in addition to mounting a major Distributed Denial of Service, or DDoS, attack, similar to the one that was recently released to the web by hosting company Cyberbunker and which has caused a worldwide slowdown in Internet speed, the hackers will also try to plant “Trojan horses” infecting web users with viruses.

Uri Rivner, head of cyber strategy at BioCatch, recommended that Israelis avoid accessing threatened websites for a few days, giving their owners time to make sure no malicious codes were installed.