Israel's indiscriminate attack on the besieged Gaza Strip raged on Thursday after a proposed truce and release of hostages was delayed for at least another day.

More than a day after plans were unveiled for the conflict's first cease-fire, the anticipated announcement of the official start time had yet to materialize. Israel said it would not begin at least until Friday.

Clouds of smoke could be seen billowing above northern Gaza's war zone from across the fence in Israel as daylight broke over the Gaza Strip, accompanied by the sounds of heavy gunfire and booming explosions.

In Rafah on the strip's southern edge where hundreds of thousands have sought shelter, residents combed with their bare hands through the ruins of a house smashed in a giant crater.

A grey-bearded man wailed in sorrow, lying among shattered masonry while another man lay his hand on his shoulder to comfort him.

The Israeli military said it had launched at least 300 airstrikes in the past day.

"The negotiations on the release of our hostages are advancing and continuing constantly," Israeli National Security Adviser Tzachi Hanegbi had said in a statement overnight. "The start of the release will take place according to the original agreement between the sides, and not before Friday."

The first pause in the seven-week-old conflict is meant to be accompanied by the release of 50 women and children hostages captured by militants who raided Israel on Oct. 7, in exchange for 150 Palestinian detainees from Israeli jails.

Israel has said the truce could last beyond the initial four days as long as Palestinian groups free at least 10 hostages per day. A Palestinian source has said a second wave of releases could see as many as 100 hostages go free by month's end.

"We are not ending the war. We will continue until we are victorious," the chief of the Israeli general staff, Lt. Gen. Herzi Halevi, told commanders in a video released by the military Thursday.

Israel launched its war in Gaza after the Oct. 7 Hamas incursion of southern Israel. Since then, more than 14,500 Gazans have been killed by Israeli bombardment, including over 6,000 children.

'Our kids are tired'

The delay to the start of the truce meant another day of fear for Palestinian families trapped inside the Gaza combat zone and worry for Israeli relatives who say they still know nothing about the fate of hostages.

"We need to know they are alive, if they're okay. It's the minimum," said Gilad Korngold, desperate for any information about the fate of seven of his family members, including his 3-year-old granddaughter, believed to be among the hostages.

At a tented camp for displaced people in Khan Younis in the south of the Gaza Strip, Omar al-Salawat had hoped a truce might make it possible for his family to return to their home.

"Every time we prepare ourselves, our souls are revived again when we hear good news. We told ourselves it's time to go back home. Then all of a sudden they say that the truce didn't work out," he told Reuters. "Our kids are tired, we want to live with our children safe and sound."

Palestinian media reported at least 15 people killed in airstrikes on Khan Younis, Gaza's main southern city. Reuters could not independently verify the toll there.

Israeli officials did not give a full explanation for the delay in the start of the truce but said full arrangements still needed to be made for the release of the hostages.

"This would appear to be a matter of finalizing the details," Energy Minister Israel Katz, a member of the security cabinet, told Army Radio in an interview.

"Israel did not announce in advance that this would happen today. The understanding was that it would happen as Friday approaches."

White House spokesperson Adrienne Watson said final logistical details for the release were being worked out. "That is on track and we are hopeful that implementation will begin on Friday morning," Watson said.

Israel's Ynet news website reported that Israel had not yet received the names of the hostages slated for release by Hamas.