Jerusalem: Israel's latest confrontation with Hamas is also playing out on the digital battlefield as each side jockeys for the virtual upper hand.
Hackers who took over the Facebook page of Domino's Pizza Israel this week warned that Hamas, the Islamist movement that controls the Gaza Strip, would unleash a fifth of its estimated 10,000-rocket arsenal on Israel in a single barrage.
Israel's Shin Bet domestic security service said text messages were circulated in its name about bogus attacks and injuries from rocket fire. Cyber assaults have risen tenfold since fighting escalated last week, industry specialists say.
Hamas is turning up its psychological warfare as it upgrades its tactics in the decades-long battle with Israel. In addition to the barrage of missiles fired into the country from Gaza, it sent a drone along the coast that briefly entered Israel's airspace.
In cyberspace, Hamas started using social networks such as Twitter, mobile phone texts, and satellite broadcasts to send messages aimed at spreading panic, according to Isaac Ben-Israel, who helped establish Israel's National Cyber Bureau and now heads Tel Aviv University's Cyber Research Centre.
"I received an announcement on my phone about an attack on the petrochemical plant in Haifa that looked as it if came from Haaretz," Ben-Israel said, referring to the Tel Aviv-based Israeli daily newspaper, which denied publishing such a report. "We haven't seen real damage but it's an indication of what can happen next time and we need to deal with it seriously."
Hamas and Islamic Jihad, Gaza's second-biggest militant group, have cyber militants working around the clock trying to hack Israeli platforms. They're also drawing on a global diaspora of hackers.
Some of the computer defences the groups are trying to breach were developed in response to Hamas' virtual war on Israel when they last clashed in 2012. During that eight-day conflict Hamas called on Palestinian software technicians the world over to attack Israeli websites; the government said there were more than 44 million attempts to bring down state sites alone.
Late on July 3, pro-Palestinian activists posted on the Israeli military spokesman's Twitter page that a Gaza-launched rocket had hit the country's Dimona nuclear reactor, causing a leak. The army denied it and said it was investigating how its page was compromised.
"We swiftly struck every part of Israel from Dimona to Haifa and forced you to hide in shelters like mice," read a July 16 message sent to Israeli mobile phones in Hebrew in the name of Hamas' military wing, the Ezzedeen Al-Qassam Brigades.
The Israeli regional council of Binyamin on the outskirts of Jerusalem later said phones had been hacked and contact lists used to send out threatening messages like the one above.
During the time hackers controlled the Domino's Facebook page, status updates included a threat to "strike deep inside Israel". After Domino's regained control, it posted an image of a masked man wearing a headband in Hamas' signature green colour, with the caption, "You can't defeat the Israeli hunger for pizza!"
Israeli hackers didn't stand idly by. They left some Hamas websites disabled for hours and others displaying content maligning the Islamist group and its leaders.
Hamas' Shehab website displayed anti-Hamas headlines on July 14 with links to an Egyptian TV clip criticising the group's leader, Khaled Mashal, for staying in one of Turkey's most luxurious hotels while Palestinians were being killed. The site's Facebook page confirmed the "Zionist attack". Other Hamas sites, including Felesteen and Alsafa, were hacked as well, The Jerusalem Post said.
Dina Beer, managing director of the Israeli Internet Association, said most of Hamas' cyber warfare on Israel has focused on defacement of websites and attacks that slow Israeli Internet service providers. Israel Railways and hospital websites were also targeted, she said.
Some satellite television subscribers were surprised on July 14 to see their regular Channel 10 programming replaced by a Hebrew message to Israeli mothers to call their sons home from the military or see them dead or captured.
Ms Beer says few of the attacks have inflicted any real damage. "The attacks aren't sophisticated; they just give the feeling that someone else is in control," she said. "It's terrorism, designed mostly to frighten: 'See, we can control your sites and do things you don't want us to do.' And it works."