It may have been a tragic case of confusion.
The Israel Defense Forces declared a four-hour humanitarian cease-fire on Wednesday. But the army said it did not apply where soldiers were already engaged and that residents who had evacuated should not return to those areas.
According to Gaza's Health Ministry, at least 17 Palestinians were killed and around 200 more were wounded when shells hit a street market in Gaza City's Shijaiyah neighborhood, "which residents thought was temporarily safe but which the Israelis considered part of an active combat zone," The New York Times reports.
Palestinians were given only about a half-hour's notice of the cease-fire.
"It was a little unclear exactly what the cease-fire meant," NPR's Emily Harris reports from Gaza.
She was nearby. "We heard some shelling and then we saw a thick, wide, black cloud rising above the skyline," she said on All Things Considered. "It's not clear exactly what explosives hit, whether it's mortars or rockets or artillery."
Harris noted that many of the area's shops have been closed and shuttered throughout most of the conflict.
"It's an area that's come under intense bombardments over the past three weeks," she says. "And Israel told everyone to leave there about 10 days ago because it's an area that they say that a lot of militants operate from there."
More than 1,300 Palestinians, mostly civilians, have been killed during the 23-day-old conflict. Israel has lost 56 soldiers and three civilians.
The Israeli army said that Hamas fired dozens of rockets into Israel Wednesday, reporting no injuries or damage. Hamas said the number was far fewer.
Israel's Security Cabinet met for four hours on Wednesday and ordered the army to continue its offensive in Gaza. An Israeli official told the Jerusalem Post that the operation has led to "significant achievements on the ground" and is damaging Hamas' "strategic apparatus."
As we reported earlier, at least 20 people were killed, according to Palestinian health officials, when a shell struck a United Nations-run school Wednesday morning in Gaza.
Both the U.N. and the White House have condemned that attack.