Lashing out verbally following an Israeli air strike that killed three members of the armed wing of Hamas, Islamic militant groups in the Gaza Strip declared the de-facto two-year-old ceasefire with Israel null and void. But an Israel official said the threat was empty.

“The armed-wings of the Palestinian Resistance Factions in Gaza promise the Israeli occupation that it will respond to their crimes against the Palestinian people. We declare that these crimes will not go unpunished, and the enemy will bear all the consequences,” declared Palestinian factions in the Gaza Strip at a in a rare joint press conference.

But, Israeli Minister of Strategic Affairs Moshe Ya’alon dismissed the threat by the Palestinians, saying the deterrence Israel hammered into Hamas during the Operation Cast Lead in 2009 was still holding strong. “Hamas is deterred from paying another price for any kind of escalation or provocation initiated by Hamas or other factions in the Gaza Strip,” Ya’alon said in a telephone interview.

The variant views came amid the biggest upsurge violence since Israeli forces entered Gaza in the 20008-2009 Cast Lead Operation. That led to hundreds of Palestinian casualties and a ceasefire that has held more or less over the past two years. Over the weekend, Hamas suffered a public relations blow when the h chairman of a United National Panel probing Cast Lead disavowed his committee’s work and said he had now concluded Israel hadn’t committed any war crimes.

In the latest exchange of fire, Israeli forces killed Isma'il Labad, 31, and his brother Abdullah, 24, from Ash-Shati refugee camp in the northern Gaza Strip, and Muhammad Ad-Dayah, 31, from the Zaytoun neighborhood of Gaza City in air strike. All three belonged to Hamas, the Islamic movement that controls Gaza.

It was this attack that prompted Hamas’ armed-wing to declared that the ceasefire over on Sunday. But as late in the day, there were no reports of rockets or other attacks coming from Gaza.

Ya’alon, a former chief of general staff of the Israel Defense Forces, said Hamas had recently declared it wasn’t interested in escalating the situation. “They are still deterred by the price that they paid in the Cast Lead operation. I believe that it hasn’t been changed yet,” he said.

Israel and the Palestinian resistance factions in Gaza have been playing the game cat and mouse lately after escalation on both sides.

It is rare for the Palestinian resistance factions to hold a joint press conference, but the original ceasefire was undertaken as a cooperative venture between them rather than between Israel and Hamas. Nevertheless, the militants express some hesitation about how and when they would act.

They told reporter they are exploring what would be the appropriate response and would exercise one or more options depending on the situation on the ground.
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“We will not accept any new dictates from the Israeli occupation on our people and the resistance factions,” their joint statement said.

Israel said the three Gazans killed in the operation were planning to kidnap Israelis on the Egyptian-controlled Sinai peninsula. But the Palestinians factions denied that. “The armed-wings confirm that the work and activities of the Palestinian resistance is limited to within the borders of occupied Palestine,” they said, meaning Gaza, the West bank and Israel.

The fighting between Israel and Gaza comes against the background of growing calls among ordinary Palestinians for Hamas and its arch-rival, the Fatah-controlled Palestinian Authority, which controls the West Bank, to end the political division and form a national unity government.

While the West Bank and Gaza have largely been spared the turmoil raging across much of the Middle East, Hamas is watching developments carefully. On the positive side, Egypt’s transition government has signaled an easing of restrictions imposed on Gaza that has helped Israel keep the enclave sealed off. But unrest has spread to Syria, which is home to some of Hamas’ key leaders.

In Sunday’s news conference, Hamas tried to avoid taking sides between the Syrian government and opposition. “ Hamas considers this matter as a purely internal issue. Hamas also declares its full support of Syrian people and leaders,” the group said.