Many Palestinians have sought shelter after fleeing their homes in southern Gaza and complained of water shortages as Israel pressed on with its military offensive in the densely populated enclave.
Israeli forces carried out new military strikes in the southern city of Rafah amid fierce fighting with Palestinian militants overnight, residents said.
At least 12 people were killed in new strikes in central and northern Gaza, health officials said.
Israel's leaders have said they are winding down the phase of intense fighting against Hamas, the Islamist group that has governed Gaza since 2007, and will soon shift to more targeted operations in the nearly eight-month-old war in Gaza.
But fighting continued overnight in two locations at the centre of Rafah, where tanks have seized several districts and advanced further west and north of the city in recent days, and concerns about the plight of hundreds of thousands of displaced people are growing.
The Israeli military said its forces had continued targeted, military-based operations in Rafah, dismantled several military sites and killed Palestinian militants.
In Maghazi refugee camp in central Gaza, two Israeli air strikes killed five Palestinians, health officials said.
In Shejaia, an eastern suburb of Gaza City in the centre of the enclave, an air strike killed four and wounded 17, medics said.
Another air strike hit a car in the southern city of Deir Al-Balah, killing three people, health officials said.
Deir Al-Balah is crowded with hundreds of thousands of Palestinians forced to flee homes elsewhere in Gaza, and residents complain of acute shortages of drinking water and inflated prices for basic foodstuffs.
The war in Gaza began when Hamas burst into southern Israel on October 7, killed about 1200 people and seized around 250 civilians and soldiers who they took back in Gaza, according to Israeli tallies.
The offensive launched by Israel in retaliation to try to eliminate Hamas has killed nearly 38,000 people, according to the Gaza health ministry, and has left the heavily built-up coastal enclave in ruins.
Internationally mediated talks have failed to secure a lasting ceasefire.
While the United States has maintained its strong support for Israel throughout the war, President Joe Biden has on some occasions expressed concerns about Israel's conduct.
A White House official said on Tuesday Biden was expected to meet Israeli Prime Minister Benjamin Netanyahu in late July when the Israeli leader visited to address the US Congress.
The Gaza health ministry said an Israeli strike on a house in the southern city of Khan Younis had killed Hassan Hamdan, head of the burns and plastic surgery department at Nasser Medical Complex, along with all his family members.
Israel's army did not comment on the ministry's statement and Reuters was unable immediately to verify it.
Khan Younis residents said a lack of designated shelters meant many families had slept on the road because they could not find tents after Israeli army evacuation orders led to the displacement of thousands of people living east of the city.
The last functioning hospital in the area, the Gaza European Hospital, which had housed displaced families as well as patients, was also evacuated.
An Israeli defence official said on Tuesday that although evacuation orders had been issued for the area in which the European Gaza Hospital is located, staff and patients were told they could stay.
World Health Organisation Director-General Tedros Adhanom Ghebreyesus said it was "devastating" that the European Gaza Hospital was out of service when access to health care was urgently needed.
He wrote on X that the Nasser Medical Complex was now at full capacity and "has a shortage of medical supplies and drugs for surgery".
