BEIT HANOUN, Gaza Strip — Thousands of Gaza residents who had fled Israel-Hamas fighting streamed back to devastated border areas during a lull Saturday to find large-scale destruction: scores of homes were pulverized, wreckage blocked roads and power cables dangled in the streets.

The 12-hour truce was the only apparent outcome from a high-level mediation mission by US Secretary of State John Kerry and UN chief Ban Ki-moon over the past week. They failed to broker a week-long cease-fire as a precursor to a broader deal, as they had hoped.

Instead, Israel’s defense minister warned he might soon expand the ground operation in Gaza “significantly.”

In the northern town of Beit Hanoun, residents encountered widespread destruction. Most had fled days earlier, following Israeli warnings that the town would be shelled.

Siham Kafarneh, 37, sat on the steps of a small grocery, weeping. The mother of eight said the home she had moved into two months earlier and spent 10 years saving for had been destroyed.

“Nothing is left. Everything I have is gone,” she said.

Israel launched a major air campaign in Gaza on July 8 and later sent ground troops into the Hamas-ruled territory in an operation it said was aimed at halting Palestinian rocket fire and destroying cross-border tunnels used by militants to stage attacks.

More than 900 Palestinians, many of them civilians, have been killed and more than 6,000 wounded over the past 19 days, according to Palestinian officials in the Hamas-ruled Gaza Strip. Israel says hundreds of the Gaza dead are Hamas gunmen. The air strikes have also destroyed hundreds of homes and displaced tens of thousands fleeing the fighting.

Israel says it is doing its utmost to prevent civilian casualties, including sending evacuation warnings to residents in targeted areas, and blames Hamas for putting civilians in harm’s way. Israel has lost 37 soldiers and two citizens, and a Thai worker has also been killed.

Saturday’s 12-hour lull appeared unlikely to change the course of the current hostilities, with both sides digging in.

Israel wants to create deterrence. “At the end of the operation, Hamas will have to think very hard if it is worth it to taunt us in the future,” Defense Minister Moshe Ya’alon said Friday.

Hamas, in turn, is unwilling to halt fire until it receives international assurances that Gaza’s seven-year-old border blockade will be lifted. Israel and Egypt tightened the blockade after Hamas seized Gaza in 2007, aiming to prevent the smuggling in of weapons.

After the temporary truce took effect at 8 a.m. Saturday, the streets of Gaza quickly filled with residents trying to stock up on supplies or returning to devastated areas to inspect their homes.

Ambulances of the Red Crescent reached the hardest-hit areas, including Beit Hanoun and the eastern Shejaiya district of Gaza City, to recover bodies buried under the rubble.

Seventy-three bodies were pulled from the rubble Saturday, many of them partially decomposed, said Gaza Civil Defense spokesman Said al-Saoudi. “Fighters” were among the dead, he said.

In two border areas, ambulances were unable to approach because tanks fired warning shots at the vehicles, the Red Crescent said.

In the southern town of Khan Younis, 20 members of the same extended family, including at least 10 children, were killed by tank fire that hit a building on the edge of town, said Gaza health official Ashraf al-Qudra.

The house partially collapsed and people were buried under the rubble. The family had recently moved into the building after fleeing fighting in a nearby village, he said.

Hundreds of men marched in a funeral procession in Khan Younis Saturday afternoon while carrying the bodies, all wrapped in white cloth and some with bloody stains. The men took turns carrying them while chanting in unison, “there is only God.”

The Israeli military said troops would respond if Gaza gunmen violate the lull. The military also said “operational activities to locate and neutralize tunnels in the Gaza Strip will continue.”

The army has so far uncovered 31 tunnels dug from Gaza and under the border with Israel, and has destroyed half of them. Israel considers the tunnels to be a strategic threat because terrorists have used them to launch surprise attacks inside the country, killing six soldiers inside Israel in five attacks this month.

The Israeli government has also begun suggesting that Gaza be demilitarized as a condition for a permanent cease-fire so that Hamas cannot rearm itself ahead of yet another round of fighting. The current war is the third in Gaza in just over five years; Hamas seized control of the Gaza Strip from Mahmoud Abbas’s Palestinian Authority in a violent takeover in 2007. Israel had withdrawn all troops and settlers from Gaza two years earlier.

Gaza terrorists have fired close to 2,500 rockets at Israel since July 8, exposing most of Israel’s population to an indiscriminate threat.

In Beit Hanoun, the streets were filled at midmorning with frantic residents, many of whom had walked several miles from temporary shelters to inspect the damage to their homes and retrieve belongings. Ambulances with wailing sirens and donkey carts loaded with mattresses and pots soon clogged the streets.

At the Beit Hanoun hospital, six patients and 33 medical staff had spent a terrifying night huddled in the X-ray department as the neighborhood was being shelled, said director Bassam Abu Warda.

A tank shell had hit the second floor of the building, leaving a gaping hole, and the facade was peppered with holes from large-caliber bullets.

On Saturday morning, the remaining patients were evacuated from the hospital, including 85-year-old Nasra Naim.

The elderly woman and a second patient were resting on mattresses on the ground floor of the hospital, amid debris and glass shards. Naim said her home was destroyed in the shelling.

“I don’t know where to go,” she said. “They (Israelis) killed our children, they took our land and now they are still following us.”

Times of Israel staff contributed to this report.