Three sons and at least two grandchildren of the Hamas leader, Ismail Haniyeh, have been killed in an Israeli airstrike in the Gaza Strip, the exiled political chief of the militant group has said from his base in the Qatari capital of Doha. Haniyeh told Al Jazeera on Wednesday that his children Hazem, Amir and Mohammed and several of their children were visiting relatives for Eid at the Shati refugee camp in northern Gaza when their car was targeted in an Israeli airstrike. Sixty of his relatives had been killed in the six-month-old war, he said, including 14 who died after an Israeli airstrike hit the family home in Gaza City in October. The Hamas leader said the attack would not change the group’s demands for a permanent ceasefire and return of displaced Palestinians from their homes in ongoing negotiations mediated by Doha and Washington. “All our people and all the families of Gaza have paid a heavy price in blood, and I am one of them,” Haniyeh said. The Israeli military statement confirmed it had targeted Haniyeh’s sons, who it described as “three Hamas operatives” who were “on their way to carry out terrorist activities”. The strike came after Joe Biden said the actionsof Israel’s prime minister, Benjamin Netanyahu, in Gaza were a “mistake”. “I don’t agree with his approach,” he said. Biden added: “What I’m calling for is for the Israelis to just call for a ceasefire, allow for the next six, eight weeks, total access to all food and medicine going into the country.” The US president’s remarks on a ceasefire marked a shift from previous comments, in which he had said the burden lay with Hamas to agree to a truce and hostage release deal. The comments, aired on Tuesday by the US Spanish-language TV network Univision, were made last week, a day before a tense phone call between the two leaders in which Biden sought answers from Netanyahu about the drone strike that killed seven aid workers from World Central Kitchen, and extracted promises that Israel would do more to protect civilians and allow more desperately needed aid into Gaza. Washington would be forced to change policy if Israel did not change its conduct in the Palestinian territory, he reportedly said. Israel responded by agreeing to open new aid crossings: 419 trucks entered Gaza on Monday, a record number for a single day since the war began. Biden has provided strong diplomatic and military support to the US’s major Middle Eastern ally since the 7 October Hamas attack in which Israeli officials say 1,200 people were killed and another 250 taken hostage. However, growing domestic and international pressure over the humanitarian catastrophe in the besieged strip has forced his administration to belatedly shift its stance. The most serious disagreement has been over Israel’s plans for a ground offensive in Gaza’s southernmost city of Rafah, where more than a million people have sought relative safety. Netanyahu has repeatedly vowed that Israel will carry out the operation. After six months of war, more than 33,400 people have been killed in the coastal territory, according to the local health ministry, and nearly all of the 2.3 million population displaced from their homes. Famine is “projected and imminent” in some areas, a UN-backed report said last month. World Central Kitchen was expected to resume aid shipments to Gaza soon, Cypriot officials said on Wednesday, after the humanitarian programme was suspended after Israel’s killing of a convoy of aid workers who had coordinated their movements with the Israel Defense Forces (IDF) on 1 April. About 1,000 tons of aid, mostly food, is waiting to be loaded in Larnaca. Israel announced on Sunday it had pulled all of its ground troops out of southern Gaza for “tactical reasons”, raising questions about the future direction of the war as hopes grew that the latest round of ceasefire negotiations in Cairo may finally bear fruit. But on Wednesday ground battles raged in several areas of the strip, killing at least 127 people, the health ministry in the Hamas-run territory said, and truce talks appeared to once again falter. The sides remain far apart on key issues, including the return of Palestinians to northern Gaza. Netanyahu’s security cabinet met late on Tuesday to discuss the hostage negotiations but did not appear to make any decisions. Also on Wednesday, the Israeli war cabinet member Benny Gantz told members of his National Unity party that “victory will come step by step”, warned that Israel was facing a long war and that it would have to fight in Gaza for years to come. Hamas seized power after a brief civil war with the rival faction Fatah in 2007, leading Israel to blockade the territory, fighting four wars and dozens of smaller conflagrations before 7 October upended the status quo in the decades-old Israeli-Palestinian conflict. The war in Gaza has sparked fears of a regional conflict, heightened last week by the killing of Gen Mohammad Reza Zahedi, a senior figure in Iran’s Islamic Revolutionary Guards, in a strike on an Iranian diplomatic building in the Syrian capital of Damascus for which Tehran holds Israel responsible. On Wednesday, Israel’s foreign minister said his country’s forces would strike Iran directly if it launched a retaliatory attack from its territory. “If Iran attacks from its territory, Israel will respond and attack in Iran,” Israel Katz said in a post on X in both Farsi and Hebrew. Earlier on Wednesday, Iran’s supreme leader, Ayatollah Ali Khamenei, reiterated a promise to retaliate against Israel over the attack on its consulate in Damascus. Israel has attacked scores of Iranian-linked targets in Syria over the years with the apparent intent of disrupting arms transfers and other cooperation with Lebanon’s Hezbollah, which is backed by Iran. Since the war in Gaza began six months ago, there have been near-daily exchanges of fire between Israeli forces and Hezbollah along the Israel-Lebanon border.