The latest battleground in the ongoing Gaza conflict exists beyond the reach of rocket fire and warplanes.
In the shadows of the escalating violence, both sides have turned to an arsenal of new media tools, such as YouTube, Twitter and the blogosphere, in an increasingly sophisticated 21st century propaganda war.
Since Israeli airstrikes on Hamas targets began a week ago, an American cybercrimes expert said thousands of Israeli and American Web sites have been defaced by radical Muslim hackers. A broad spectrum of sites, including those belonging to small businesses, a media company and a cargo airline, have been hacked into and plastered with anti-Israeli and anti-American messages.
One site featured an illustration of a young man's bloody hand and the words: "Israel. … One day, all peoples of the world will wake up and when they wake up they will destroy your state and the USA…" Other sites broadcasted far more incendiary messages and graphic images.
The Israeli government ramped up a digital campaign of its own this week that features a YouTube channel to show footage of precision bombing and a Twitter feed to host discussion of the conflict.
"The blogosphere and new media are another war zone," Maj. Avital Leibovich, the head of the Israeli Defense Forces' foreign press branch, told the Jerusalem Post. "We have to be relevant there."
As social media and digital technologies shift battleground lines, experts say this week's cyberskirmishes underscore the need for the United States to quickly create a long overdue cybersecurity strategy.
Attacks like this week's -- that deface Web sites to spread propaganda -- may inflict relatively minimal damage, but experts warn that the coordination of the attacks suggests that greater threats are looming.
As soon as Israel began its bombing campaign last week, Gary Warner, the director of research in Computer Forensics at the University of Alabama at Birmingham, said he noticed a drastic uptick in the number of defacements of Israeli sites.
In a 48-hour period, he said, anti-Israeli hackers based in Turkey, Iran and elsewhere violated the security of more than 300 Web sites and replaced the existing content with their own messages and images.
Although the sites featured images of injured children and inflammatory, expletive-laden language, Warner said the cyberattacks were strictly intended to spread propaganda.
"They are veiled and probably useless threats," he said.
Warner said that because he is working with law enforcement he is unable to share many specific details about the hackers' locations and profiles. But he and his colleagues have been monitoring several international groups for years, some of which coordinate about 10,000 hackers.
Although some of the hackers Warner monitors are world class, he said, many are low-skill recruits who are enlisted and then trained to perform "script kiddie" attacks. These hackers don't need real technical expertise, just enough know-how to run someone else's program, he said.
"It really doesn't take a lot of skill to become involved in this kind of attack, it just takes motivation," Warner told ABCNews.com. For those who want to support the cause but don't necessarily want to be a martyr, this is "a low-risk way to become involved in the conflict."