JERUSALEM —The hostilities between Israel and Hamas have found a new battleground: social media.The Israeli Defense Forces and Hamas militants have exchanged fiery tweets throughout the fighting in a separate war to influence public opinion.

Shortly after it launched its campaign Wednesday by killing Hamas' top military commander Ahmed Jabari, the Israeli military's media office announced a "widespread campaign on terror sites & operatives in the (hash)Gaza Strip" on its Twitter account.

It then posted a 10-second black-and-white video of the airstrike on its official YouTube page. Google Inc., which owns YouTube, removed the video for a time early Thursday, but reconsidered and restored it.

A tweet from (at)idfspokesperson said: "We recommend that no Hamas operatives, whether low level or senior leaders, show their faces above ground in the days ahead."

Hamas, under its (at)AlQassamBrigade English-language account, which is largely considered to be the official Twitter account for its military wing, fired back: "Our blessed hands will reach your leaders and soldiers wherever they are (You Opened Hell Gates on Yourselves)."

The Israeli military's media office Twitter account, which gained more than 50,000 followers in just 24 hours, is just one of various online platforms used to relay real-time information to the public, sometimes even before it is conveyed to reporters.

The IDF news desk's email signature reads like a catalog for new media platforms, including links to its YouTube channel, Facebook page and Flickr photo albums. The military also just opened a Tumblr account in English and plans to launch one in Spanish.

Following the assassination, the military tweeted a graphically designed photograph of Jabari, with a red backdrop and capitalized block letters reading "ELIMINATED," drawing both celebration and fierce criticism from a range of users. Throughout the operation, the military and its supporters have tweeted with the hashtag "IsraelUnderFire," while many Palestinians have tweeted with a separate hashtag "GazaUnderAttack."

The operation, launched after days of rocket fire from Gaza into southern Israel, marks the most intense round of violence since Israel and Hamas waged a three-week war four years ago.

Palestinian militants fired more rockets into Israel on Thursday, killing three people and striking the outskirts of Tel Aviv. Israeli strikes have killed 15 Palestinians.

Military spokeswoman Lt. Col. Avital Leibovich said that in the four years since Israel and Hamas last dueled, an "additional war zone" developed on the internet.

"I'm sort of addicted to Twitter, you can say. It's a great tool to release information without the touch of editors' hands," she said. "Militaries are usually closed operations, but we're doing the opposite."

Leibovich is also the head of a two-month-old "Interactive Media" branch of the IDF, staffed with around 30 soldiers trained in writing and graphic-design skills. As an indicator of the significance of the department to the military, Leibovich said she'll be leaving her current spokeswoman's post in February to focus solely on running the interactive branch.

The Hamas media wing has dramatically improved its outreach from the days when their loyalists used to scrawl graffiti on walls in the Gaza Strip.

Hamas' militant wing keeps a frequently updated Facebook page and a multilanguage website. They tend to update reporters of rocket fire through an SMS distribution list.

Nader Elkhuzundar, a prolific 25-year-old Twitter user from Gaza, said the recent social media barrage reached "a new level of psychological war."

"Twitter gives us a voice, but there's also a lot of misinformation at the same time. It's a tool you need to be careful using because there's a lot of noise out there," he said.

Although there were tweets directed at the IDF's Twitter account claiming that the Israeli government and military websites were hacked and taken down Thursday, the Israeli military denied it.

"The IDF blog was down for a very short period, less than hour in the afternoon, only due to heavy traffic," according to Eytan Buchman, an Israeli military spokesman.

Israel's ministry of public diplomacy also started a "Special Operations Center," a virtual situation room of sorts, working with Israeli bloggers and volunteers to "get Israeli's message out to the world virtually, to Arabs as well, through social media and other web platforms," said spokesman Gal Ilan.

Tamir Sheafer, chair of the political communication program at Hebrew University, said the embrace of social media by both sides indicates recognition that "you don't win conflicts like this one on the ground; you win it through public opinion."

But the use of social media for public diplomacy is also a double-edged sword, says Natan Sachs, a fellow at the Brookings Institute in Washington.

"On the one hand, Israel has gotten better in conveying their messages to the public, but on the flip side, we're seeing flippant remarks. Twitter accounts can be used carelessly and there's a danger of overplaying things, which they might be doing," he said.

"They also might be falling into the trap of thinking they have their public relations covered, but really, it's their policy and not their tweets that matters at the end of the day," Sachs added.

YouTube had removed the Hamas assassination video after concluding the clip violated its terms of service. The site's reviewers later reconsidered that decision and restored the video Thursday.

"With the massive volume of videos on our site, sometimes we make the wrong call," YouTube said in a statement.

Buchman, the Israeli military spokesman, said there was no official comment, except that "we're glad they reconsidered that decision."

Google tries to ensure that the clips on YouTube obey disparate laws around the world and adhere to standards of decorum while also protecting the principles of free speech. It's a mind-boggling task, given more than 100,000 hours of video is sent to YouTube every day.

YouTube routinely blocks video in specific countries if it violates local laws. It also removes video deemed to violate standards primarily designed to weed out videos that infringe copyrights, show pornography or contain "hate speech."

Given that YouTube isn't regulated by the government, Google is within its legal rights to make its own decisions about video. Nevertheless, some people believe Google should always fall on the side of free expression because YouTube has become such an important forum for opinion, commentary and news.

A video showing an assassination arguably falls in a gray area of whether it is a news event or a gratuitous act of violence.

This isn't the only assassination that can be watched on YouTube. Numerous clips on YouTube replay the fatal shooting of U.S. President John F. Kennedy in 1963, including his gruesome head wound.

Google doesn't share details about how its video reviews are conducted, but it employs an unknown number of reviewers who regularly scan the site for violations of local laws and the company's guidelines.

Google discussed its approach to Internet content in a November 2007 blog post that came about a year after buying YouTube for $1.76 billion.

"We have a bias in favor of people's right to free expression in everything we do," wrote Rachel Whetstone, Google's director of global communications and public affairs, "We are driven by a belief that more information generally means more choice, more freedom and ultimately more power for the individual. But we also recognize that freedom of expression can't be — and shouldn't be — without some limits. The difficulty is in deciding where those boundaries are drawn."

Usually, the decisions are dictated by the law in the more than 100 different countries where Google's services are offered. The laws in some countries prohibit material that would seem tame in other countries. For instance, Brazil prohibits video ridiculing political candidates in the three months leading up to an election, while Germany outlaws content featuring Nazi paraphernalia.

In the first half of this year alone, Google said it received more than 1,700 court orders and other requests from government agencies around the world to remove more than 17,700 different pieces of content from its services.

The company rejects many of these demands. For instance, Google says it complied with less than half of the U.S. court orders and government orders take down nearly 4,200 pieces of content from January through June.