The Palestinian group announced the death in a statement on Tuesday after Israel confirmed it had hit Bahaa Abu al-Atta, 42, in an attack.Shortly after the attack, salvos of rockets were launched from Gaza into Israel, with sirens wailing across central and southern parts of the country.
Meanwhile, Islamic Jihad said an attack was carried out on the home of Akram al-Ajouri, one of its officials, in the Syrian capital, Damascus, killing al-Ajouri's son and at least one other person.
Mulhaimar Abu Sadaa, a professor at Al Azhar University in Gaza, says the besieged city might witness "further escalation" after Israel killed Palestinian Islamic Jihad commander Bahaa Abu al-Atta in a strike on his home in Gaza, prompting retaliatory rocket fire.
"We are going to witness further escalation in the coming hours and days, but it all depends on the behaviour of Hamas," he told Al Jazeera.
EU urges "complete de-escalation" after Israel Gaza strike
The European Union on Tuesday called for a "rapid and complete de-escalation" after Israel killed Palestinian Islamic Jihad commander Bahaa Abu al-Atta in a strike on his home in Gaza, prompting retaliatory rocket fire.
"The firing of rockets on civilian populations is totally unacceptable and must immediately stop," the EU's diplomatic service said in a statement.
Palestinian man killed, 12 others wounded, in fresh Israeli air strike
Spokesman of Gaza’s Health Ministry, Ashraf al-Qudrah, told Al Jazeera that one Palestinian has been killed in an Israeli air strike that targeted the northern Gaza Strip.
Mohammed Attiyah Musleh Hammouda, 20, was killed in the attack, and 12 others were wounded, according to al-Qudra.Islamic Jihad leader vows to "face Israeli crimes"
"[Israeli PM Benjamin] Netanyahu will pay a hefty price for the assassination of Abu al-Atta … His troops and settlers will pay a hefty price for these crimes," Khaled al-Batsh, an Islamic Jihad leader, told crowds in Gaza.
"Today, we tell our people, the only option available is to face [this aggression]," he said in televised remarks.
Hamas spokesman Hazem Qassem, said the Israeli attacks and the assassination of Abu al-Atta is a "continuation of Israeli aggression towards the Palestinian people".
"Our people are being targeted all over, inside and outside Palestine," he told Al Jazeera Arabic from Gaza.
"The attack reflects Israel’s unsuccessful tactics … Assassinations cannot and will not put an end to resistance, and are not enough to stop Palestinians from supporting the cause," Qassem said.
"After every attack, the will of the resistance grows and becomes more persistent," he added.
Hamas, which governs the Gaza Strip, is coordinating with all of the Palestinian factions in Gaza to respond to the "occupation’s crimes", Qassem said."We call on the international community to intervene immediately to stop Israeli aggression,” Palestinian government spokesman Ibrahim Melhem, told Al Jazeera Arabic from the occupied West Bank city of Ramallah.
"The president is in contact with the relevant parties to ensure the safety of our people in the Gaza Strip."
Israel's Iron Dome System intercepted missiles, which were fired from the Gaza Strip in response to Israeli strikes that killed senior Islamic Jihad commander Bahaa Abu al-Atta and his wife.
The rockets, according to /Israeli local media, were intercepted over the southern city of Ashdod.
Widespread anger in Gaza
Al Jazeera Arabic’s Wael al-Dahdouh, reporting from Gaza, said there is a "high degree of anger” in Gaza.
"The overnight operation reminded people in Gaza of previous assassinations that targeted Palestinian activists and high-level commanders from Palestinian resistance groups in their homes," he said"
"Anger is also among the various Palestinians groups in Gaza … because an attack on the Islamic Jihad means potential attacks on other groups as well."
Netanyahu to deliver statement
Israeli Prime Minister Benjamin Netanyahu and his Chief of Staff, Aviv Kochavi, are set to deliver statements to media at 8:30 GMT.
Damascus raid 'carried out with several missiles'
Syrian state media said the Israeli attack in Damascus had been carried out using several missiles, one of which was shot down over the nearby suburb of Daraya.
At the scene of the attack, a Reuters news agency witness said the top floor of a two-storey building had been completely scorched.
Syrian state media said two were killed, including the son al-Ajouri, and six people were wounded in the attack, on the home in al-Mazzeh, a western district of the capital where several foreign embassies are located.
