Haniyeh confirmed the deaths Wednesday in an interview with the Al Jazeera satellite channel, saying his sons “were martyred on the road to liberating Jerusalem and the Al-Aqsa Mosque.”
There was no immediate comment from the Israeli army.
“The criminal enemy is driven by the spirit of revenge and murder and does not value any standards or laws,” he said in the phone interview.
Ismail Haniyeh lives in exile in Qatar, where Al Jazeera is based.
He said the killings would not pressure Hamas into softening its positions. The two sides have been involved in months of ceasefire talks.
“The enemy believes that by targeting the families of the leaders, it will push them to give up the demands of our people,” he said. “Anyone who believes that targeting my sons will push Hamas to change its position is delusional.”
Hamas’ Al-Aqsa TV station said Hazem, Ameer and Mohammed Haniyeh were killed with family members in the strike near the Shati refugee camp in Gaza City. Ismail Haniyeh is originally from Shati.
The brothers were traveling with family members in a single vehicle targeted by an Israeli drone, Al-Aqsa TV said. It said a total of six people were killed, including a daughter of Hazem Haniyeh, and a son and daughter of Ameer.
The strike comes as international mediators have been trying to broker a new ceasefire agreement. It was not immediately clear what effect the strike would have on those talks.
Earlier, Israeli war cabinet minister Benny Gantz claimed Hamas has been defeated militarily, although he also said Israel will fight against it for years to come.
“From a military point of view, Hamas is defeated. Its fighters are eliminated or in hiding” and its capabilities “crippled,” Gantz said in a statement to the media in Sderot.
But, he added: “Fighting against Hamas will take time. Boys who are now in middle school will still fight in the Gaza Strip.”
Gantz reiterated the Israeli’s government commitment to go into Rafah, the city in the far southern tip of the Gaza Strip where more than half the territory’s population is now sheltering. “Wherever there are terrorist targets – the IDF will be there,” he said.
The strike came as Palestinians in Gaza marked a muted Eid Al-Fitr holiday ending the holy fasting month of Ramadan, visiting the graves of loved ones killed in the war. In the Jabaliya refugee camp near Gaza City, people sat quietly by graves surrounded by buildings destroyed by Israel’s offensive in response to the deadly Hamas attack on Oct. 7.
