NEW YORK — As the battle in Gaza grinds on, an unprecedented technological skirmish is taking place in cyberspace. On the Israeli side, the IDF’s Wednesday morning tweet announcing the launch of Operation Pillar of Defense marked the first military declaration of hostilities via Twitter in history.

Now the IDF may be facing an organized response from a group of hackers claiming to be part of the international hacker coalition Anonymous, who published on Thursday their own declaration of cyber-war on Israel and its supporters.

In a press release posted Thursday to an Anonymous-affiliated website, the hackers warned Israel not to shut down the Internet in Gaza and to cease its military operations in the coastal strip, which come on the heels of a barrage of hundreds of rockets from Gaza into Israel in recent days.

“To the IDF and government of Israel we issue you this warning only once,” read the press release. “Do NOT shut down the Internet into the ‘Occupied Territories’, and cease and desist from your terror upon the innocent people of Palestine or you will know the full and unbridled wrath of Anonymous. And like all the other evil governments that have faced our rage, you will NOT survive it unscathed.”

In a widespread effort called #OpIsrael, Anonymous hackers promised to take down over 40 Israeli government and military websites.

Despite the IDF’s official blog disappearing for a brief moment on Thursday, it appears the effort has fallen flat, with only a handful of small websites, including falcon-s.co.il and advocate-israel.com, suffering outages.

Shortly after noon on Friday, the group also managed to briefly bring down the website of AIPAC, the influential Washington-based lobby for stronger US-Israel ties, though AIPAC managed to restore the site within the hour.

Anonymous last attacked AIPAC’s website in March, bragging about the feat on Twitter.

Israeli hackers appeared to be returning fire Friday, as the Anonymous Twitter feed reported that an Anonymous-affiliated IRC network (which hosts online chat rooms) ”appears to be under heavy attack by pro-Israeli cyber groups.”

In addition to its attacks on Israel, Anonymous has developed an “Anonymous Gaza Care Package,” a file containing “instructions in Arabic and English that can aid you in the event the Israel government makes good on it’s (sic) threat to attempt to sever your Internet connection.”

The file also contains “useful information on evading IDF surveillance.”

In addition, hackers have worked to provide Gazans with chat rooms and communications channels that are more difficult for Israeli security services to observe. A list of dialup phone connections to European Internet service providers has been published to allow Gazans to access the Internet through regular phone lines in the event that Internet access in the Strip is shut down.

While the Anonymous campaign has yet to score meaningful victories, and Israeli hackers appear to be responding vigorously, Anonymous has vowed the campaign will be long and painful.

“For far to (sic) long, Anonymous has stood by with the rest of the world and watched in despair the barbaric, brutal and despicable treatment of the Palestinian people in the so called ‘Occupied Territories’ by the Israel Defense Force (sic),” it said in the Thursday press release.

“To the people of Gaza and the ‘Occupied Territories’, know that Anonymous stands with you in this fight. … know that tens of thousands of us in Anonymous are with you and working tirelessly around the clock to bring you every aid and assistance that we can.”

AIPAC did not return requests for comment.