Israel pounds Gaza for a second day in most violent assault in months as UN envoy heads to Cairo for mediation talks.
Islamic Jihad’s armed wing announced the killing of Bahaa Abu al-Ata in a statement after Israel confirmed it targeted the 42-year-old leader.
Separately, the Palestinian group said Israel also attacked the home of one of its political leaders in the Syrian capital, Damascus.
Islamic Jihad said Abu al-Ata’s wife was also killed in the blast that ripped through their home in Gaza City’s Shejaiya district before dawn. At least two others were wounded, according to medics.
The group said Abu al-Ata was killed during “a heroic action”, without elaborating, and promised to take revenge.
“Our inevitable retaliation will rock the Zionist entity,” it said, referring to Israel.
Hamas, the Palestinian organisation that administers the Gaza Strip, said Israel “bears full responsibility for all consequences of this escalation”, and promised Abu al-Ata’s death “will not go unpunished”.
The Israeli military said Prime Minister Benjamin Netanyahu had authorised the operation against Abu al-Ata, blaming him for recent rocket, drone and sniper attacks against Israel, and attempted infiltrations into the country.
“Abu al-Ata was responsible for most of the Palestinian Islamic Jihad’s activity in the Gaza Strip and was a ticking bomb,” it said, accusing al-Ata of planning “imminent terror attacks through various means”.
Gaza has been under a joint Israeli-Egyptian blockade for more than 10 years, and the freedom of movement for the population of two million has been severely curtailed.
Al Jazeera’s Harry Fawcett, reporting from West Jerusalem, said the killing of Abu al-Ata marked “an extremely dangerous escalation”.
“Israel has not targeted leaders in this way for some time, so this strike is seen here as one which brings significant risks,” he said.
Shortly after the attack, dozens of rockets were launched towards Israel as air raid sirens sounded across southern and central parts of the country, including the commercial capital, Tel Aviv, the Israeli military said.
Rocket fire caused damage and injuries with at least one projectile hitting a house and another narrowly missing passing cars on a highway. A factory in the city of Sderot was also struck, sparking a fire.
Israeli medics said they treated 39 people for wounds.
Israeli police said they closed some roads on the edge of Gaza as a precaution, while crossing points between Israel and Gaza were also closed. Schools and some ministries in Gaza were also shuttered.
Fawcett reported rockets continued to be blasted into the country late Tuesday.
Netanyahu warned a protracted period of fighting could follow.
“Israel is not interested in escalation, but we will do everything required to protect ourselves,” he said. “This could take time. What is needed is stamina and cool-headedness.”
The European Union called for a “rapid and complete de-escalation”.
Mulhaimar Abu Sadaa, a political science professor at Al Azhar University, told Al Jazeera there was likely to be an escalation between Israel and armed groups in Gaza, depending on the behaviour of Hamas.
“If Hamas is going to join the Islamic Jihad we are going to approach further escalation with Israel, but if Hamas is able to contain the Islamic Jihad, with the help of the Egyptians, the situation might be contained or brought under control within two to three days,” he said.
“The Islamic Jihad is the second strongest military organisation in Gaza, after Hamas, and there is a lot of competition between the two groups. It is not easy to say that Hamas will be able to contain the Islamic Jihad. I think the Egyptians and other international mediators like the UN will probably have to be brought in to contain this cycle of violence.”
“Generally speaking, Islamic Jihad is funded and supported militarily and politically by Iran, so maybe Iran will play a role whether this cycle of violence will be extended or brought to an end soon.”
Separately on Tuesday, Syrian state media said that Israel launched a missile attack targeting the home of an Islamic Jihad official in the Syrian capital, killing his son and granddaughter.
A Syrian official said Israeli fighter jets fired three missiles towards Damascus one of which was intercepted, while the other two struck the home of Islamic Jihad political leader Akram al-Ajouri in Mezzah, a western district of the city, according to state news agency SANA.
Al-Ajouri’s son Muath and granddaughter Batoul were killed, the official was cited as saying, while nine others were wounded.
Islamic Jihad said al-Ajouri survived the attack on his home and blamed the “Zionist criminal enemy”.
There was no immediate comment from Israel.
The attack comes at a sensitive time in Israeli domestic politics, as Prime Minister Netanyahu heads a caretaker government following two inconclusive elections. His main political rival Benny Gantz, a former chief of the Israeli military, is currently trying to form a coalition government.
“There has been some criticism in Israeli politics, notably from the Palestinian-Israeli Joint List members, accusing Netanyahu of engaging in this as a desperate last attempt to hold on to power,” Fawcett said.
“Gantz … says that this was the right decision. He has been recommending a tougher response on Gaza for many months.”
Earlier this week, Netanyahu appointed far-right politician Naftali Bennett as his defence minister. Bennett has long advocated stronger action against Palestinian armed groups in Gaza.