JERUSALEM — Palestinian Islamic Jihad militants fired a barrage of rockets at Jerusalem early Sunday, in the latest round of fierce cross-border attacks that began on Friday with Israeli strikes against the Gaza-based group.

Egyptian-mediated talks for a cease-fire were advancing on Sunday, according to an official familiar with the discussions, raising hopes for a cessation of hostilities within the next 24 hours.

Still, the situation remained volatile as militants continued to fire rockets in the afternoon, first at closer range, aimed at Israeli territory along the Gaza border, and, much further afield, toward the suburbs south of Tel Aviv. The Israeli military said it was continuing to hit Islamic Jihad rocket launching sites.

The earlier salvos by the militants, which occurred just after 8 a.m. Sunday, came as hundreds of Orthodox Jews marked a somber fast day by visiting a holy site revered by both Muslims and Jews in the Old City of Jerusalem. Warning sirens wailed in villages in the surrounding hills.

There were no immediate reports of casualties; most of the rockets launched by the militants over the past two days have been ineffective, with the vast majority either intercepted by Israel’s Iron Dome defense system or falling in open areas, according to the Israeli military. The militants have fired almost 600 rockets at Israel.

Israel had pounded the blockaded and impoverished coastal enclave of Gaza with air and artillery strikes on Friday and Saturday, saying it was attacking Islamic Jihad military targets, including some located in residential buildings.

In Gaza, residents emerged after a night of bloodshed amid what has become the most violent conflagration between Israel and Gaza militants in more than a year.

At least 31 people have been killed so far in Gaza, according to the Health Ministry there, and 275 have been injured. Six children were among the dead, the ministry said on Sunday.

Israel said some of those children were killed on Saturday night when an Islamic Jihad rocket misfired and fell short in the northern Gaza Strip. The Israeli military said it had not been operating in that area at the time. Islamic Jihad has not commented on the Israeli claim.

Israel’s military also chalked up what Israeli officials and analysts hailed as an important operational success on Saturday night with the killing of Khaled Mansour, a senior Islamic Jihad commander responsible for the southern region of Gaza.

Islamic Jihad confirmed the commander’s death early Sunday. His body was found under the rubble of a building in a residential area along with the bodies of two more militants and five civilians, including a child.

“We affirm that the blood of the martyrs will not be spilled in vain,” the military wing of Islamic Jihad said in a statement, adding that Mr. Mansour’s death “will ignite the battle to defend Jerusalem and the blessed Al-Aqsa Mosque,” referring to the holy site in the city that Jews revere as the Temple Mount.

Mr. Mansour’s death came a day after Israeli strikes killed the military commander of Islamic Jihad’s northern region, Taysir al-Jabari. Earlier in the week, Israel had arrested a senior figure from the group in the West Bank, leading to threats of reprisals. Israel said its initial airstrikes were pre-emptive, aimed at stopping Islamic Jihad from following through on those threats.

Hamas, the much larger Islamic militant group that dominates in Gaza, has so far stayed out of the fighting, a factor that could limit the scope and duration of the conflict.

The last major Gaza conflagration, fought over 11 days in May 2021, began after Hamas fired a barrage of rockets toward Jerusalem following days of Israeli-Palestinian confrontations there.

Lt. Col. Richard Hecht, a spokesman for the Israeli military, said on Sunday that “quiet will be answered with quiet, but if they keep firing we will keep acting,” repeating a position Israel has articulated many times before as it tried to wind down past campaigns in Gaza.

Iyad Abuheweila, Gabby Sobelman and Fady Hanona contributed reporting.