A propaganda war is being waged on the internet between supporters of the Israeli and Palestinian sides in the current conflict in the Gaza Strip.
Activists have turned to defacing websites, taking over computers, and shutting down Facebook groups.
US Military sites, Nato, and an Israeli Bank have all been targeted.
Experts have warned users to be on the lookout for phishing emails and webmasters to ensure their servers are secure.
The hacking of security barriers for political or ideological reasons has been branded by some as hacktivism. And it is thought that as use of the internet grows, so too will the number of attacks.
On 7 January, pro-Palestinian hackers defaced several high-profile websites, including a US Army website, and the Nato Parliamentary Assembly's website.
Calling themselves "Agd_Scorp/Peace Crew", they replaced pages with white space and a well-known photograph of a boy throwing stones at an Israeli tank in Gaza, and the Israeli, American and British flags with a red strike through them.
"Stop attacks u israel and usa ! you cursed nations ! one day muslims will clean the world from you!" wrote the hackers.
Dwight Griswold, the Nato Parliamentary Assembly's head of IT, says that the attackers persisted in attempting access for a number of days following the initial attack, adding that the intruders did not gain access to any of the Assembly's internal servers.
The battle also looms large on social networking site Facebook, where dozens of groups related to the conflict in Gaza have sprung up.
The clash flared up when a group using the logo of the Jewish Internet Defence Force (JIDF) took control of several of these groups.
They removed content and replaced it with statements supporting Israeli policy and criticising the Palestinian militant group Hamas, which controls Gaza, and replaced the groups' images with the JIDF logo.