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 is the only apparent outcome from a high-level mediation mission by U.S. Secretary of State John Kerry and U.N. chief Ban Ki-moon over the past week. They failed to broker a weeklong 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 spent 10 years saving up for and moved into two months earlier 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.

At least 985 Palestinians, mainly civilians, have been killed and more than 6,000 wounded, according to Palestinian officials. Israeli strikes have destroyed hundreds of homes and forced tens of thousands of people to flee.