Israel’s government is facing a growing clamour to trade the estimated 229 hostages in Gaza for thousands of Palestinian prisoners in Israeli jails. Families of the hostages gained prominent support on Sunday in their effort to persuade Benjamin Netanyahu’s administration to negotiate a swap with Hamas. Giora Eiland, a former head of the Israeli National Security Council, and the newspaper Haaretz swelled the chorus of calls to exchange about 5,000 Palestinians – including Hamas militants – for the captives in Gaza. Some relatives delivered that message in a blunt meeting with Netanyahu on Saturday in Tel Aviv, where they have set up a camp opposite the defence ministry. On Sunday a delegation asked the president, Isaac Herzog, to keep the hostages top of the political agenda. “We do not feel that the issue is a priority for the state,” said Jackie Levy, three of whose relatives have been abducted. The government had lapsed into petty politics and the president needed to be the “responsible adult”, she added. Relatives planned to release balloons with messages to the captives at a ceremony on Sunday night. The intensifying assault on Gaza – where the death toll after three weeks of bombing has passed 8,000, according to the Hamas-run health ministry – added urgency to the appeals. In Rome, Pope Francis called for a ceasefire and the release of hostages. The prisoner swap campaign added pressure on Netanyahu as he performed an abrupt U-turn after attempting to deflect blame for the intelligence and security failures that allowed Hamas militants to rampage through southern Israel on 7 October, killing more than 1,400 people. Early on Sunday morning, the prime minister tweeted that security chiefs, including the head of military intelligence and the head of the internal security agency Shin Bet, had believed Hamas was deterred and had no plans to attack. “This was the evaluation that was submitted time and again to the prime minister,” Netanyahu said. Hours later he deleted the tweet and apologised. “I was wrong,” Netanyahu said in a new post. “I fully back all the heads of the security establishment.” The debacle prompted rebukes even from his allies and fuelled a widespread perception that the prime minister wished to evade accountability for the worst attack in Israel’s history. “When we are at war, leadership must display responsibility,” said Benny Gantz, an opposition leader who recently joined the emergency unity government. The opposition leader Yair Lapid said Netanyahuh had “crossed a red line” and weakened the Israeli Defence Forces. Yossi Cohen, a former Mossad intelligence chief, said: “Responsibility is something you take at the start of your job, not midway.” The government has said the return of hostages is a goal on par with defeating Hamas, but some families fear the military offensive could kill their loved ones through shelling or Hamas reprisals. Hamas said up to 50 hostages had died in bombing last week, without offering verification. “Every day they are not released, they are in jeopardy,” said Zeev Scherman, a cousin of Ron Scherman, a missing 19-year-old. The leader of Hamas in Gaza, Yahya Sinwar, said on Saturday the group was ready for an immediate swap of all Palestinian prisoners in Israeli jails in return for Israeli captives in Gaza. An Israel Defence Forces spokesperson said the statement’s timing was “psychological terror” and that the army was doing everything possible to recover the hostages. The Israeli defence minister, Yoav Gallant, said the offensive was partly intended to induce Hamas to make concessions. “If there is no military pressure on Hamas, nothing will progress.” Some hostages’ relatives support the offensive and oppose any prisoner swap that would include members of Hamas. Militants freed in the 2011 swap for the Israeli soldier Gilad Shalit were involved in the 7 October attack. Ayelet Samerano, whose son Jonathan was abducted, expressed confidence in the IDF strategy. “My army knows exactly what to do.” The Hostages and Missing Families Forum, an umbrella name for groups of relatives, has avoided making prescriptions. “We are telling the army and the government to bring back our people,” said Haim Rubinstein, a spokesperson. “We are not telling them how to do it.” Relatives who favour a prisoner swap have become more outspoken and gained influential support. Eiland, the former security adviser, who is also a retired major general, said saving the hostages was the most urgent challenge. “Israel would be right to make two concessions to secure the release of all of the hostages: to release all 5,000 Palestinian prisoners incarcerated in Israel, and to postpone temporarily a more aggressive operation in Gaza,” he wrote in the newspaper Yedioth Ahronoth. A Haaretz editorial said the hostages must come first. “The state does not have the mandate to sacrifice 229 people; no one would give it that mandate. Nor can it be allowed to consciously, for tactical reasons, make these people collateral damage in the war against Hamas.” Israel must release all Palestinian security prisoners, said the newspaper. “Whatever it takes to bring the hostages home immediately. At once. Today.”