Medics said they had recovered 19 bodies of Palestinians killed in northern areas of Nuseirat, one of the enclave's eight long-standing refugee camps.
Later on Friday, an Israeli air strike killed at least 10 Palestinians in a house in Beit Lahiya in northern Gaza Strip, medics said.
Others were killed in the northern and southern areas of the Gaza Strip, medics added.
There was no fresh statement by the Israeli military on Friday but on Thursday it said its forces were continuing to "strike terror targets as part of the operational activity in the Gaza Strip".
Israeli tanks had entered northern and western areas of Nuseirat on Thursday.
They withdrew from northern areas on Friday but remained active in western parts of the camp.
The Palestinian Civil Emergency Service said teams were unable to respond to distress calls from residents trapped in their homes.
Dozens of Palestinians returned on Friday to areas where the army had retreated to check on damage to their homes.
Medics and relatives covered up dead bodies, including of women, that lay on the road with blankets or white shrouds and carried them away on stretchers.
"Forgive me, my wife, forgive me, my Ibtissam, forgive me, my dear," one grief-stricken man moaned through tears beside her corpse, laid out on a stretcher on the ground.
Israel's military campaign has reportedly displaced nearly all of the Gaza Strip's population. (AP PHOTO)
Medics said an Israeli drone on Friday had killed Ahmed al-Kahlout, head of the Intensive Care Unit at Kamal Adwan Hospital in Beit Lahiya, on the northern edge of the Gaza Strip, where the army has been operating since early October.
Contacted by Reuters, the Israeli military said it was unaware of a strike occuring in this location or timeframe.
Kamal Adwan Hospital is one of three medical facilities on the northern edge of the Gaza Strip that barely function now due to shortages of medical, fuel and food supplies.
Most of its medical staff have been detained or expelled by the Israeli army, health officials say.
The Israeli army said forces operating in Beit Lahiya, Beit Hanoun and Jabalia since October 5 aimed to prevent Hamas militants from regrouping and waging attacks from those areas.
Residents said the army was depopulating the towns of Beit Lahiya and Beit Hanoun as well as the Jabalia refugee camp.
Meanwhile, Israeli authorities released about 30 Palestinians whom it had detained in the past few months during its Gaza offensive.
Those released arrived at a hospital in southern Gaza for medical checkups, medics said.
Freed Palestinians, detained during the war, have complained of ill-treatment and torture in Israeli detention after they were released.
Israel denies torture.
Months of efforts to negotiate a ceasefire in the Gaza Strip have yielded scant progress, and negotiations are now on hold.
A ceasefire in the parallel conflict between Israel and Lebanon's Hezbollah, an ally of Hamas, took effect before dawn on Wednesday, bringing a halt to hostilities that had escalated sharply in recent months and had overshadowed the Gaza conflict.
Announcing the Lebanon accord on Tuesday, US President Joe Biden said he would now renew his push for a ceasefire agreement in Gaza and he urged Israel and Hamas to seize the moment.
Israel's campaign in the Gaza Strip has killed nearly 44,300 people and displaced nearly all the enclave's population at least once, Gaza officials say.
Vast swathes of the territory are in ruins.
The Hamas-led militants who attacked southern Israeli communities 13 months ago, triggering the war, killed about 1200 people and captured more than 250 hostages, Israel has said.
