Israeli airstrikes early Wednesday killed 20 Palestinians in central Gaza, including six children and three women, some of them inside a purported “safe zone” declared by the Israeli military, hospital authorities said.

This second straight night of deadly strikes in the central town of Deir al-Balah and nearby refugee camps came as U.S., Egyptian and Qatari mediators as well as Israeli officials came together in the Qatari capital, Doha, for talks trying to push through a long-elusive deal for a cease-fire and hostage release.

Israel and Hamas had appeared to narrow the gaps in recent days, but obstacles remain.

Strikes early Wednesday hit three houses in the Nuseirat refugee camp, killing 12 people including five children, said authorities at al-Aqsa Martyrs Hospital, where the casualties were taken. An Associated Press reporter counted the bodies.

The camp, like others around Gaza, was originally erected to house Palestinians driven from their homes during the 1948 war surrounding Israel's creation. It has grown into an urban neighborhood in the decades since.

A fourth strike early Wednesday killed four men, three women and a child when it hit a home in Deir al-Balah, an area that is located within the “humanitarian safe zone” where Israel has told Palestinians to seek refuge as it conducts offensives in multiple parts of the Gaza Strip.

The overnight bombardment came hours after Israeli warplanes struck the entrance of a school sheltering displaced families outside the southern city of Khan Younis. The toll from the strike rose to 31 people killed, including eight children, and more than 50 wounded, officials at the nearby Nasser Hospital said Wednesday.

Footage aired by Al-Jazeera television showed kids playing soccer in the school's yard when a sudden boom shook the area, prompting shouts of “a strike, a strike!”

The Israeli army said the airstrike near the school and reports of civilian casualties were under review, and claimed it was targeting a Hamas militant who took part in the Oct. 7 attack on Israel, though it provided no immediate evidence. The military blames civilian deaths on Hamas because the militants fight in dense, urban areas. But the army rarely comments on what it is targeting in individual strikes, which often kill women and children.

In nine months of bombardment and offensives in Gaza, Israel has killed more than 38,200 people and wounded more than 88,000, according to the territory's Health Ministry, which does not distinguish between combatants and civilians in its count. Nearly the entire population has been driven from their homes. Many have been displaced multiple times. Hundreds of thousands are packed into sweltering tent camps.

Israel's onslaught was triggered by Hamas' cross-border raid on Oct. 7, during which militants killed 1,200 people in southern Israel, most of them civilians, according to Israeli authorities. The militants took roughly 250 people hostage. About 120 are still in captivity, with about a third said to be dead.

This week, Israeli troops have also been waging a new ground assault in Gaza City in the north of the territory — its latest effort to battle Hamas militants regrouping in areas the army previously said had been largely cleared.

Large parts of Gaza City and urban areas around it have been flattened or left a shattered landscape by previous Israeli assaults, and much of the population fled earlier in the war. But the latest incursions and bombardment prompted a new flight of people.

After Israel on Monday called for an evacuation from eastern and central parts of Gaza City, staff at two hospitals — Al-Ahli and the Patients Friends Association Hospital — rushed to move patients and shut down, the United Nations said.

The Israeli military said Tuesday that it told hospitals and other medical facilities in Gaza City they did not need to evacuate. But hospitals in Gaza have often shut down and moved patients at any sign of possible Israeli military action, fearing raids.

In the past nine months, Israeli troops have attacked at least eight hospitals, causing the deaths of patients and medical workers along with massive destruction to facilities and equipment. Israel has claimed Hamas uses hospitals for military purposes, though it has provided only limited evidence.

Only 13 of Gaza's 36 hospitals are functioning, and those only partially, according to the United Nations' humanitarian office.

International mediators were making a new concerted effort to push through a proposed cease-fire deal.

An Egyptian official said the head of Egypt's General Intelligence Service, Abbas Kamel, went to Doha to join discussions over the deal. The official said U.S. and Israeli officials were also attending. The official spoke on condition of anonymity because he was not authorized to brief the press on the meetings.

A day earlier, CIA Director William Burns, who has led the American mediation, met with Egyptian President Abdel Fattah el-Sissi in Cairo

Obstacles remain in the talks, even after Hamas agreed to relent on its key demand that Israel commit to ending the war as part of any agreement. Hamas still wants mediators to guarantee that negotiations conclude with a permanent cease-fire.

Israel has rejected any deal that would force it to end the war with Hamas intact. Hamas on Monday accused Israeli Prime Minister Benjamin Netanyahu of “putting more obstacles in the way of negotiations,” including the operations in Gaza City.